October Review / November Preview

October ended pretty nicely, but it didn't start out that way. Let's take a look back:

High Temperatures

Last month we talked about how September 2018 was one of the coldest Septembers ever recorded in Edmonton. And that coldsnap dragged on for another two weeks into October.

But then on October 14th our temperatures finally shot up above average again, for the first time since September 7th, more than a month earlier. Then we broke an all-time record on the 17th at 24.7°C. And we finished the month just a little bit warmer than average...although still well above what we'd seen for a lot of September.

Looking at the numbers, the average High of 10°C was just a little bit on the cooler side of things. Recent years have ranged from 2015 at 14.3°C down to 2016 at 5.7°C.

We had 1 day which hit 20°C, when about 1/3 of the time we don't get any in October. We only had 5 days which hit 15°C, which is more than a year like 2016 with 0, but less than 2014 with 14. And we had 2 Highs below freezing, which is unusual, but not impossible. The last time that we had a High below freezing in October was in 2013, but the year before that October 2012 had 10 of them.


Low Temperatures

The Lows also started well below average, and ended around the average.

The average Low of -0.9°C was also a bit on the cool side, but still above years like 2012 at -2.1°C  and 2002 at -2.7°C.

We had 21 Lows below freezing, which is a lot. In terms of recent years that ties 2009 for the most. We only had 1 Low below -5°C though, compared to 2012 and 2004 which both had 10. And we didn't have any October Lows below -10°C.


October Overall

When we combine the Highs and Lows, the mean temperature this October was 4.6°C. That's below the 20th century average of 5.3°C, and ranks 2018 as 92nd-warmest October out of 138. This chart also shows the Highs & Lows separately, and they both ranked in the low 80s.

One thing that is interesting in this chart is that the average Low temperatures for October have increased over the last century - from about -2°C to +1°C. But the average Highs have actually dropped a bit - from 12°C to 10°C. We didn't see that in September, and it's not very common in other months either. That will probably be the subject of a future post.


Warm & Cold Months

For this year so far then, October ranks as the 5th month that was below the 20th Century average - along with February, March, April and September. January and May-August were all warmer than the 20th Century average.


The Horserace

The end of October is really the point where we transition into real-winter (instead of fake-September-winter). So now is a good time to see how 2018 compares over all.

When we sum up all of the temperatures for the year, right now 2018 is sitting just a bit above the 20th century average. That puts in at the lower end of recent years, along with 2009, 2014 and 2013, and ranked somewhere around 50th~70th overall. Following the red line, we can see the sharp dip we took during the September coldsnap.


Precipitation

After our very precipitation-y September, October was right around average at 20mm. And Blatchford was just a bit below the International, at 16mm. Last year we had just a bit more, with 25mm.


Snow

And after our extremely, record-breakingly snowy September, October's 8cm was right on the average. Last October we had almost twice as much, at 15cm.



Even though we didn't get a whole lot of snow in October, the International did record 6 days with snow. That's down from 8 in September, but above the 4 last year, and the average of 3.


Snowdepth

At the cold start of the month we had snow on the ground for about a week - shown here in the orangey/gold. But once things warmed up, it disappeared.

October isn't typically the month when we get lasting snow though. But the first few weeks of November is when it usually shows up, as we make the jump into winter.


November Temperatures

...and speaking of winter, here is the recent temperature history for November.

The good news is that there are frequently still a lot of days above freezing - recently 2006 had 7 and 2017 had 9, but plenty of years were up around 20. The less good news is that about half of the time November is when we'll see our first -20°C of the winter.