October Review / November Preview

We'll start this monthly recap a little differently than most:

The Race for Warmest-Recorded Year

This chart is a day-by-day comparison of how warm 2016 has been relative to other warm years from Edmonton's history. It's a bit complicated, and if you're interested in what it all means it's probably easiest to go back to read: How warm is 2016? (September Edition)

2016 had been in the lead since early April, but on October 18 it dropped into a tie for warmest year with 1981. Since then 2016 opened up a slight lead again, so lets take a closer look:

This shows the same information as the first chart, but zoomed in on July through December. We can see that 2016 really nosedived for two weeks in early October, before leveling out again.

All of the red dotted lines are trying to show where 2016 might end up, based on the performance of the last 10 years. To stay in top spot 2016 doesn't have to be hot (20°C in December isn't required) it just needs to be warmer than the average. So if this November-December is as warm as 2011's was then 2016 will take top spot. A repeat of last year would put 2016 in 3rd place, and just below 1981 and 1987. And if the end of the year is pretty average then 2016 would probably still finish around 3rd, while a couple of really cold months could drop it down to 7th or lower.

How did 2016 lose its lead?

Here are the daily High temperatures for the month, and we can really see the coldsnap from October 5th through 18th. In that stretch almost every day was below the 25th percentile and 4 days were the coldest recorded since 1996.

For the whole month, only 7 days had Highs above the 1996-2015 average, and the other 24 were colder than average.

Here's a similar chart, but showing the daytime Lows rather than the Highs. It tells a similar story, with 18 days below the average, but things did pick up near the end of the month.

Looking at December, we can see how much the temperature range starts to spread out during the winter. In September the lows might range from 15°C to -5°C, but in December that spread doubles and can be from 5°C all the way down to -35°C.

20 Years of Temperatures

These tables always have a lot going on, but I like to use them to spot the blocks of colour. For example, it's easy to see that 2003, 2008 and 2015 all had High temperatures above 25°C which are shown in red. Or for 2016, that there was a long stretch of just-above-0°C from the 5th through the 18th.

2016's average High was 6°C which ties for coldest October since 1997 with 2002, 2009 and 2012. But even though the average is the same as those years, in 2016 we didn't actually have any Highs below 0°C (although we also didn't have any above 15°C, which had never happened since 1997).

The Lows are similar, and looking at the beginning of the month we can see the big block of white cells that have Lows below 0°C. Just eye-balling off the table the only comparable stretch was the end of October in 2004.

The average low for the month of 0°C is pretty middle-of-the-road. Even with that stretch of cold days, in 2016 we didn't dip down below -10°C and into the blues like 2002, 2003, 2004 and 2012 all did. But was also only had 1 Low that was above 5°C, which is on the cool side of things.

What can we expect from November?


Again looking at the colours as much as anything, we still see a fair number of oranges, for High temperatures above 5°C. But there are also blocks of blue creeping in, including November highs below -20°C in 2006 and 2014.

For the Low temperatures the oranges are pretty much gone in November, and most nights will drop below 0°C. And again we see blocks of blue, with late-November lows below -25°C in 2003, 2006, 2010, 2011 and 2014.

Finally, we'll take a look at precipitation.


Here we have the monthly precipitation numbers for the year. With all of the snow and general gloom we've had this month, October 2016 comes in second place in the last two decades, at just a little bit below 2006.

And for cumulative precipitation for the year 2016 is still above average, and just above the 75th percentile.

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