2020/02/01

January 2020 Review / February 2020 Preview

Today we are going to take a relatively quick look back at Edmonton's weather for January 2020.

The reason that today will be quick is because the big story for January 2020 was the deepfreeze, and we already talked about that at great length in Deepfreeze: January 2020!

Here were some of the highlights from Deepfreeze 2020, and how it compared to Deepfreeze 2019:


And now, let's talk about the rest of the month.


High Temperatures

When we look at the High temperatures for the month the deepfreeze really stands out, with Highs below -15°C and well below average stretching from January 9th through 19th.

We had 4 coldest-in-30-years Highs, with the coldest on the 14th at -29.7°C. That is still a few degrees warmer than the coldest-since-1880 records, which are mostly around -32°C to -34°C. But for some trivia, the coldest High ever recorded at the Blatchford stations was -40°C on January 30th, 1893.

Aside from the deepfreeze January's Highs were mostly a few degrees above average, and also mostly a few degrees below the top of our January range. But January 1st's High of 3.8°C was the warmest New Year's day since 5.6°C in 1964. Although 2019 was 2.9°C, 2016 was 1.4°C, and 2015 was 3.2°C, so a warm New Year's wasn't unheard of.


By the end of the month we had had 13 days with Highs of 0°C or more, which is just a bit above the average of 12 days.

We didn't have any Highs hit 5°C, although we came close with the 25th, 30th & 31st all hitting 4.6°C. On average in January we actually have 4 Highs which hit 5°C (surprise!), and since 2000 the only January's with 0 were 2000, 2008, and now 2020.

On the cold side of things we had 6 Highs of -20°C or colder, which matched 2011 & 2004. Those included 4 Highs of -25°C or colder, and that was the most since January 1996 & 1982 which also both 4. Going a bit further back, January 1980 had 5.



Low Temperatures

The Lows look a lot like the Highs, although the "mild" Lows at the end of the month mostly stayed a little bit closer to the average. From January 9th through 19th the Lows were below -20°C , with the 15th way down at -37.6°C. That was the coldest day recorded at Blatchford since January 19, 1996 at -37.8°C.

We talked about this a lot over in Deepfreeze: January 2020! if you are interested.


And so January 2020 had:
  • 11 Lows of -20°C or colder, the most since January 2011 with 12.
  • 8 Lows of -25°C or colder, the most since January 2004 with 8.
  • 4 Lows of -30°C or colder, the most since January 1997 with 6.

It is worth mentioning that the deepfreeze hit Calgary & Regina fairly hard too, and it brushed Winnipeg. You can use the dropdowns in the dashboards to compare the cities.


Warm & Cold Months

Even with the deepfreeze January's average High of -7.9°C was only the coldest since 2005's -8.1°C, and it ranked 2020 as Edmonton's 70th warmest January Highs out of 139.

If you flip this dashboard to the Lows, January 2020's average Low of -17°C was the coldest since 2004 at -17.8°C. That ranked 2020 as the 66th warmest Lows for January.

That is quite a bit different from deepfreeze of February 2019, which was not quite as cold but was much longer. It dropped February 2019's average temperature far enough to make it our 5th coldest recorded February.



In this chart we have the mean temperature for each month (average of the High & Low) compared to the average for the 20th century. Orange bubbles were warmer, and blue bubbles were colder, and the size of the bubble represents how far from the average the month was.

January 2020 ends up on the positive side of things, with a mean temperature 1.1°C above the 20th century average. That's still quite a bit colder than the past few years, because from 2012-2018 we had 8 January's in a row that were at least 4°C warmer than the 20th century average. And in the past 20 years we have had lots of warm January's and lots of warm bubbles. So 2020 ends up as our coldest January since 2004, which was down at -0.5°C below the 20th century average.

Here we can again see just how much more extreme the deepfreeze of February 2019 was, with a big blue bubble for its temperatures -9.4°C below the 20th century average for February.



At the end of January we are a little over halfway through winter. Things started off with a really cold early-November, but after that were fairly mild until the giant deepfreeze. With the warm end to January it can feel like spring is just around the corner...but actually there are still about 2 months where anything could happen.


Snow

In terms of snow January's 26.7cm makes it our snowiest month of the winter so far, and it was just a bit above our January average of 22cm.



Here we have the January snow for a few other cities around Canada:
  • everyone was laughing at Vancouver (because hey, why not?) but their 34.6cm was more than Edmonton, and the most since 36.9cm in January 2002.
  • Calgary had a very snowless January with only 3.9cm. That was the lowest since 3.2cm in January 2001.
  • Montréal's 48.2cm was right on their average.
  • And St. John's 160ish cm is just an estimate, because Environment Canada's for the giant storm are missing. 160ish cm would only be about St. John's 5th most snowy January, because it also crossed the 160cm mark in 2005, 2003, 1960 & 1912, and in 1897 it recorded 188cm.


This one is a little bit messy, but it shows the total snowfall so far this winter.

Edmonton has had 70.3cm of snow, which is right on our average.

In comparison Calgary's very snowy fall puts it at 118cm, and a little above Montréal's 113.4cm. St. John's is out of this world at more than 250cm.


Snowstorms

On January 22nd we had a fairly large snowstorm, which dropped 10.5cm on the International. That was only the International's 2nd 10cm snowday this year, after 11.4 on November 9th. Those were also our only 5cm snowdays, although a few overnight storms broke that mark too.


Snowdepth

Even with the relatively warm end to January our snowdepth is still above average with Blatchford at 24cm and the International at 25cm. The warm weather really made a dent in the International's snowdepth though, because on the 24th it had been up at 34cm.

On average our snowdepth continues to climb for more than another month, before the big melt usually starts in early March.



And so right now the International has had snow on the ground for just under 3 months, and at Blatchford it has been just over 2. And there are probably still at least 2 months to go, with Blatchford's snow usually hitting zero around the beginning of April, and the International sometimes a bit later.


Here's a quick comparison of the snowdepths in Edmonton, Calgary, and St. John's. Calgary is down at 1cm, which is pretty typical for them. St. John's was way up at 125cm following the storm, but that has fallen to 71cm.


February Temperatures



February temperatures are usually a lot like January, with 10-15 Highs above 0°C, and 5 Lows below -20°C.

But of course last year February 2019 was ridiculous. It had just 1 High of 0.0°C, and then 21 Lows hit -20°C, including 16 at -25°C, and 3 at -30°C. Let's all agree to never do that again.

2020/01/19

Deepfreeze: January 2020!

It is finally over, and so now let's take a look back at the great deepfreeze of January 2020.
If you are viewing this in the future all of the dashboards will include post-2020 data as well. So they will show the deepfreeze of 2020, plus any deepfreezes which may have come after it. If you want to see the charts as they looked originally, those are all in this twitter thread (assuming that twitter still exists in the future).

Today we will be talking about the deepfreeze of January 2020, and we will see that it set a lot of coldest-in-X-years records. But before we get to that it is important to mention that less than one year ago we also had the great deepfreeze of February 2019.


February 2019

We talked about the deepfreeze of 2019 in detail here, and it had its own set of coldest-in-X-years records:
  • 9 Lows in-a-row of -25°C or colder: the most since 1996.
  • 18 Lows in-a-row of -20°C or colder: the most since 1996 again.
  • 11 Highs in-a-row of -15°C or colder: the most since 1998.
  • 18 Highs in-a-row of -10°C or colder: the most since 1996 again.
Overall February 2019 ended up being our 5th coldest February since 1880, and our most below-average month since February 1979.

So during the 12 months from February 2019 to January 2020 we had two, separate coldest-in-a-generation (or two generations) deepfreezes. 

And now...

January 2020

The deepfreeze of February 2019 was very long, but the deepfreeze of January 2020 was very cold.


-37.6°C!

Probably the biggest shock of the January 2020 deepfreeze was that Blatchford had a low of -37.6°C on January 15th.

The last time that we hit -37°C had been 8,761 days earlier on January 19, 1996 at -37.8°C. And prior to that Blatchford's last -37°C had been 8,757 days earlier on January 27th, 1972. That January 1972 deepfreeze was also that last time that Blatchford hit -40°C, with a Low of -41.1°C on January 26th, 1972.

This also ended our streak of Lows above -35°C at 3,684 days. The last time we had hit -35°C was December 13, 2009 at -36.7°C. That had been the longest the we had gone without a -35°C, and the 2nd longest was 2,556 days from 1997 to 2004.


January 15th, 2020's Low of -37.6°C was only our *5th* coldest January 15th: 1896 hit -43.9°C, 1950 hit -40°C, and 1907 & 1930 hit -38.3°C.

And the High of -27.5°C was our 6th coldest, with the record of -33.3°C in 1896.


As is usually the case, Blatchford was the warmest location in the Edmonton region, with many of the surrounding stations about 5°C colder, and the International airport reaching -42.3°C. A 5°C difference is actually fairly small, because often on very cold days there will be an 8°C or 10°C difference between the city and the airport.


Lows of -30°C: 4 in-a-row

January 15th's -37.6°C was the coldest that we got, and was also the only day to hit -35°C. But we still had 4 Lows of -30°C in-a-row, with January 13th at -31.3°C, the 14th at -34°C, the 15th at -37.6°C, and the 16th at -30.7°C.

4 Lows of -30°C in-a-row made that Edmonton's 62nd longest streak. In "recent" memory 1997, 1996, 1989 & 1982 also all had 4 day streaks. Going a bit further back 1980 & 1977 both went 6 days. And the big standouts were 1954 with 14 days, 1893 with 13, and 1887 with 16.

So we hadn't seen one of these in 22 years, and before that they used to be quite a bit more common.

This chart shows when throughout the year we get our Lows of -30°C.

In recent years our -30°C Lows have stretched from as early as December 6th in 2013, to as late as March 10th in 2009. January has had the most with 18, followed by December with 9, February with 6 (even though people are always hating on February), and then March with 4.

Looking back through history to the 1880s the range for -30°C Lows stretched all the way to early November, although late-January has been when they have most frequently arrived.

In the 21 years since 2000 Blatchford has only recorded 37 Lows of -30°C. In the 10 years from 1990-1999 there were 42, and going further back the 1960s had 82, the 1930s had 124, and etc.


Lows of -25°C: 7 in-a-row

For Lows of -25°C in-a-row this deepfreeze went 7, from January 12th through 18th.

That was 2 days less than the 9 days in-a-row in February 2019. But other than 2019, this was the longest streak since 1996 with 12 days.

Prior to the 1980s 10 Lows in-a-row of -25°C were quite common, happening 30 times from 1880-1980. The longest streak was 26 days during the infamous deepfreeze of January 1969.

So we saw one of these last year, but prior to that it had been 22 years.


Lows of -20°C: 11 in-a-row

For Lows of -20°C we went 11 in-a-row, which was well below the 18 in February 2019. In recent years we had gone also 9 days in 2018, 2011, and twice in 2008.


Highs of -30°C: None (just barely)

Our coldest High of this deepfreeze was -29.7°C on January 14th. While that is really, really close to -30°C, we didn't technically have any Highs of -30°C.

The longest recorded period without a High of -30°C was 6,215 days from January 26, 1972 to January 31st, 1989. As I write this in January 2020 we are in the 2nd longest streak at 5,840ish days, going back to January 27, 2004.

January 14th, 2020 did end our streak of days without a High of -29°C at 5,830 days (going back to January 27, 2004 again). The 2nd longest streak without a -29°C was 3,979 days from 1954 to 1964.


Highs of -25°C: 4 in-a-row

We had 4 Highs in-a-row of -25°C or colder.

In recent years 2004, 1997, 1989, 1984 & 1982 were all just below that at 3. To find a year with more than 2020 we need to go back to 1980 & 1977 which both went 5 days. The record was 1936 with 14.


Highs of -20°C: 6 in-a-row

And finally, we had 6 days with Highs of -20°C or colder, from January 12th to the 17th.

That was the most since 1998 which had 12, and the big standout is once again January 1969 with 26. In recent years 2004 had also gone 6, and 2011 & 2003 went 5.


Calgary

Calgary was also hit with this deepfreeze, although it was not quite as severe as in Edmonton:

  • Calgary's lowest temperature was only -32.4°C on January 15th.
  • They had 3 -30°C Lows, 7 -25°C Lows, and 11 -20°C Lows in-a-row.
  • They had 4 -25°C  Highs, and 4 -20°C Highs in-a-row.

All of the dashboards here also include the data for Calgary, and that can be selected using from the dropdown on the upper-right. The data for Regina and Winnipeg is also there, and they also had a few cold days, but Alberta really got the worst of it.


Recent Deepfreezes

This chart is not my favourite, because it can get incredibly messy incredibly quickly. But here it is set to show the temperatures for streaks of 11 or more Lows of -20°C in-a-row. So 2020 is here with 11, and 2019 has 18. There are a few 13s and 15s in the 1990s, and the big one was 23 days in February 1996.

The rainbow dots in the lower portion of the dashboard show all of the 11-day streaks going back to 1880. Prior to 2000 things like this happened quite frequently, but then there is the big gap between 1997 & 2019 because these just are not very common anymore.

On this dashboard you can change the temperature ranges to see how January 2020 lined up with other deepfreezes, but again, the chart gets very busy very fast.


Overall

This chart is also a little messy, but it shows the average Low temperatures for each January & February going back to 1881.

The deepfreeze of February 2019 was so long that it made February 2019 our 5th coldest February overall. The deepfreeze of January 2020 was colder but also shorter, and so as I write this at the end of the deepfreeze it is only roughly our 30th coldest January. And with a warm week ahead that will likely change by the end of the month.


Summary:

We've had two first-time-in-a-generation deepfreezes within the past 12 months. February 2019 was long, and January 2020 was cold.

January 2020 notables:
  • The first Low of -37°C since 1996, and the first -35°C since 2009.
  • 4 Lows of -30°C in-a-row, which was the most since 1997.
  • 7 Lows of -25°C in-a-row, which was the most since 1996, except for the 9 in 2019.
  • 11 Lows of -20°C in-a-row, which was the most since 1998, except for the 18 in 2019.
  • The first High of -29°C since 2004.
  • 4 Highs of -25°C in-a-row, which was the most since 1980.
  • 6 Highs of -20°C in-a-row, which was the most since 2004.

February 2019 notables:
  • The most -25°C Lows (9) & -20°C Lows (18) in-a-row since 1996.
  • The most -15°C Highs (11) & -10°C Highs (18) since the mid-late 1990s
  • It was the coldest month since January 1982, and the coldest February since 1979.

Looking at all of the charts today there are big gaps between these two most recent deepfreezes and the previous ones in the mid-1990s, or the early-1980s. In recent years we had not seen these types of extended cold temperatures, but prior to 1980 these deepfreezes would not have been particularly unusual.

2020/01/11

2019 in Review - Part 2 - Precipitation

And we're back with a (relatively) quick look back at 2019's precipitation. In Part 1 we looked at 2019's temperatures.


Total Precipitation


2019 finished the year with 464.7mm of combined Precipitation (Rain + Snow equivalent) at Blatchford, and the International was 35mm lower at 429.2mm. The yearly average is 440mm, so Blatchford was a bit above that, and the International was just below.

That is a reversal compared to both 2017 & 2018 where Blatchford was 100mm below the International.


Other Cities


For comparison, here are the yearly totals for several other Canadian cities, compared to Edmonton's typical range.

  • Regina was down at 375mm, which is right on their average.
  • Winnipeg isn't shown here because it's too close to Edmonton, but it was at 457mm, and just below their average of 500mm. 
  • Calgary's 525mm was quite high compared to their average of 435mm.
  • Ottawa's 900mm was just below their average of 928mm.
  • Toronto's 949mm was well above their average of 813mm.
  • Vancouver's 966mm was well below their average of 1,178mm.
  • Montréal's 1,196mm was well above their average of 1,031mm.
  • And St. John's 1,405mm was actually low compared to their average of 1,610mm (which sounds ridiculous to me).

Today we will really be focusing on Edmonton, but if you want more details on the other cities the overall precipitation is here, and the snow is here.


Monthly Precipitation


Here we are back to Edmonton again, and the stations for Blatchford and the airport.

The two big precipitation stories for 2019 were a very dry spring, and then a very wet summer.

For March, April & May Blatchford recorded only 25.9mm of precipitation, compared to a 5-year average of 87mm for those months. That might actually be Blatchford's driest recorded spring. 2009, 2011 & 2015 all technically have lower totals, but they are also all missing a month or more of data (you can click through them in the dashboard). For years with all 12 months of data the next lowest was 1898 with 27.9mm for March, April & May.

The International recorded 42.9mm for March, April & May. That was more than Blatchford, but it was still in the bottom-5 for the airport, going back to 1961.

In the summer things switched around with a rainy June, and a very rainy July.

The June average is 75mm, and the International recorded 85.6 with Blatchford up at 117.4mm. For July the average is 90.6, and the International was at 118.6mm and Blatchford was way up at 163.4mm.

Blatchford's 163.4mm in July was its 7th highest, and the most since 1982. The record was 282.7mm from way back in 1901. June & July at Blatchford combined for 280.8mm, which was its 6th rainiest June & July, and the rainiest since 1988.

Other than that the rest of the months: January, February, and August-December were all pretty typical.


Days with Precipitation


Here we have the days each month that had recorded precipitation.
  • January & February were a little high at Blatchford, and were really high at the International. The averages are 10 & 8 days respectively, and the International had 17 & 15.
  • March, April & May were all low at both stations, which isn't surprising given the dry spring. The average for those months is 9-10 days, and in March we were down at 2 and 3 days.
  • The rainy summer had a few more rainy days than usual. The average is about 15 days, and Blatchford and the International were at 17-20 days.
  • September & October had a few more rainy days than average.
  • November was well above the average of 9 days, with the International at 13 and Blatchford at 17.
  • And we ended the year with an average December.

Big Storms

This chart shows all of the "big" storms with more than 20mm of precipitation for Blatchford. Blatchford used to record snow & rain separately, but that stopped in about 2007, so now we just know that there was precipitation.

And Blatchford had 5 big storms in June & July, with the largest on July 17th at 38.8mm. That's a pretty big storm, and most years will have one day around 40mm or more.

If you switch this dashboard to show the International (at the lower left) it only had one 20mm day, with 25mm on July 19th. And so the big difference in the June & July numbers for Blatchford and the International were because several of the big storms which hit Blatchford mostly missed the airport.


Snow

Switching over to snow, here we have the snowfall for each month of 2019 for the International.

It wasn't a very exciting year, with a slightly low January, slightly high February, slightly low March & April, and then everything else was pretty average.

The total snowfall for the year was 111.2mm, which ranks as #39 out of 58 for the International. The average is around 125mm, so this was a bit low.

Normally when we talk about snow we talk about "winters" (Oct-Apr) rather than the Calendar Years (Jan-Dec) that this dashboard uses. The rest of the charts today will be using winters, and they will be a little bit less straight, but hopefully they will still make sense.


First & Last Snow

Last spring the last snowfall at the International was on May 4th, which was about a week later than the average of April 26th. Looking back over the years that average has moved around, but late-April is right in the middle of the range for both stations.

The first snow of the fall was on October 7th which is pretty average, but which was much later than 2014, 2016, 2017 & 2018 which had all been in early-mid September. The very early snows during the past few autumns have pushed the average date to September 22nd, which is just about as early as it has ever been. It was briefly earlier in the mid-1970s with an average first snow of September 16th. But even 10 years ago in 2010 the average first snow was a month later at October 24th.

So 2014, 2016, 2017 & 2018 were all very early, and 2019's October 7th was more typical, but still on the early side of things.


Lasting Snow

In the spring the snow at the International disappeared on March 31, and for Blatchford it was April 1. That is on the early side of things, although several recent years were earlier.

(Blatchford also shows a blue stripe of 5cm of snow in late May, and that totally did not happen. But it is in Environment Canada's data, but I 100% know that it is incorrect. I'm leaving it here as a reminder that sometimes data that looks weird really, truly is wrong.)

In the fall the snow started to hang around at the International on November 5th. That wasn't as early as 2017 or 2018 which were right around Halloween, but it was still pretty early. For Blatchford the lasting snow started several weeks later on November 27th, and that is fairly typical for Blatchford.


Snowdepth - Spring


This chart shows the snowdepth for the winter of 2018-2019, so the right half has the spring of 2019.

In 2019 February and early-March were very cold, so there was no melting. The snowdepth at both Blatchford and the International were over 30cm, and well over the average of about 20cm.

Once the the cold finally broke the big melt happened quickly. Snowdepth at the International fell from 45cm to 0cm between March 10th and March 31st. Blatchford fell from 37cm on March 9th to 1cm on the 24th, and then hung on for another week before finally melting.

Snowdepth - Fall

And here we have the snowdepth for the winter of 2019-2020, with the right half as the autumn of 2019.

The snowdepth at both stations spiked at the beginning of November with a big storm, but at Blatchford that melted-off while the International stayed at about 10cm. Both stations gained snow through December, and Blatchford ended the year below average at 8cm, with the International above average at 22cm. (then things spiked again in January).


Snowstorms

Finally, this dashboard shows every "large" snowstorm each winter. Here the cutoff is set to 5cm, but that can be raised or lowered with the slider.

2019 had 2 snowstorms of 10cm or more: March 8th with 12.8cm, and November 9th with 11.4cm.

And there were 2 more storms of 5cm or more: February 1st with 6cm, and April 30th with 6.2cm.

We average about 7 5cm storms each year, but for 10cm storms 1 or 2 is pretty typical.


And that brings us to the end of the 2019 Year-in-Review: Precipitation. The most interesting parts were the very dry spring followed by the very wet summer, and other than that things were pretty normal.

First -20°C & -25°C of the Winter of 2019-2020

It finally happened: on January 9th we got our first -20°C Low of the winter, and then on January 10th the first -25°C showed up. How late were they?

"Technicalities"


First up, we just need to admit that while January 9th was the first -20°C of the winter, we came very close on November 11th at -19.6°C.

We will see today that January 9th is quite late for a -20°C, but November 11th was very early for a -19°C - the earliest since 2012, and before that 1995.

So -20°C is just an arbitrary cutoff, but we need to draw a line somewhere, so that's what we are going to talk about.

Recent -20°C Lows


Our first true -20°C Low was January 9th, at -24.2°C, and that is quite late in the winter. For 2010-2015 they all happened in November, but then 2016 was December 7th, 2017 was December 24th, and 2018 was December 30th.

Other recent winters which made it all the way to January without a -20°C were 2002-2003 on January 11th, 1997-1998 on January 1st, 1987-1988 on January 3rd. Those are all highlighted here:



One thing to notice about those winters is that even though they had a late -20°C, by the end of the winter they all still ended up with around 20 -20°C Lows. On average we get 22~25 so 1987-1988 and 1997-1998 we maybe a little bit below normal, but they still got most of a winter's worth of cold days, even though they started pretty late. A late start to winter does not necessarily mean a mild winter.

Ye olde -20°C Lows


Here we've gone back to the beginning of the records for comparison.

The winter of 1918-1919 made it all the way to January 1st for it's first -20°C, but for a lot of years they were in early-mid November.

1880-Today


And when we look at all of it together we can see the slow decline over the past century, from an average of about 50 -20°C Lows each winter down to about 25.


Recent -25°C Lows


Our first -20°C on January 9th was quickly followed by a -25.8°C on January 10th. That was also quite late.




Here we have a few of the other, recent, late -25°C lows.

On average we hit -25°C 8-10 times per winter. 2015-2016, 2005-2006, 1991-1992 & 1982-1983 were all well below that, but 2007-2008 & 2001-2002 both ended up around average, even with the late start.

The winter of 1986-1987 was the only one in Edmonton to not record a single -25°C.

1880-Today

Looking at the full history again, over the past century the average has dropped from about 25 -25°C Lows to around 8-10 now.