October 2021 Review

It's time for our look back at the weather in Edmonton for October, 2021.

(if you are reading this in the distant future some of the dashboards below may have updated to reflect new data or formatting, or they may be broken, or they may no longer make sense. To see the original images for this post please refer to this twitter thread.)

Unfortunately, October 2021 needs an asterisk next to it, because the Blatchford station was down for most of the month.    

Environment Canada is now using the South Campus station, and we will too. In this chart the daily temperatures for 2021 for Blatchford are blue, and South Campus are pink.

On average the stations are within ±0.1°C, but individual days can differ by a degree or two.


High Temperatures

Using the South Campus numbers October 2021 was warm~ish, but it didn't get particularly hot. 21 days had warmer-than-average Highs, and 10 were cooler.

October 2021 had 1 day reach 20°C, with 20.4°C on the 16th. A single 20°C days is pretty typical for October. 

October also had zero Highs below 5°C, which hadn't happened since 2011. October averages around 7 Highs below 5°C, including 2 below freezing.

Sadly, we've probably seen our final 20°C High of the year. 

2021 ends with 105, which is a little bit above the long-term average of 95~100. 

Edmonton has reached 20°C 5 times in November, but the most recent was on November 3, 1949.


Low Temperatures

October 2021's Low temperatures were also warm~ish, but not particularly hot. 21 nights were warmer than average, and 10 were cooler. The coldest was the 31st at -7°C.

On average October has 13 Lows below freezing, and 2021 had 14.

We only had one night below -5°C though, when the average is 3. In recent years, October 2020 & 2019 both had Lows below -10°C.


Fall Frosts

Blatchford's first fall frost was October 7th, which is about 2 weeks later than average. Stony Plain's was also October 7th. The airport's was a bit early, way back on September 3rd. And Campsie's (100km northwest of Edmonton) was a little late on September 17th.


Warm & Cold Months

The average High for this mild~ish October 2021 was 11.7°C, which ranks as the 60th warmest October on record. The average Low of 0.1°C was the 52nd warmest. 

October is one of the few months (along with April) where our average temperatures have not changed much over the past century.

October 2021 is our 5th warm month in a row, although it was much closer to average than the hot June-September of 2021.


Across Canada

For cities across Canada October was another warm month, especially in Winnipeg through Montréal, which had Highs 2-3.5°C warmer than the 20th century average. Edmonton and Calgary were closer to average, and Vancouver and St. John's were both cooler than average.


Precipitation

October averages 21mm or precipitation, and 2021 was close to that. Stony Plain had 26.7mm, the airport had 22.8mm, and South Campus had 19.7mm. (no numbers from Blatchford, unfortunately)

Our average yearly precipitation at the end of October is 402mm.

For 2021 the airport is at 310mm, Stony Plain is at 276mm, and South Campus is at 234. (Blatchford has no readings for October, but would be at ~220mm, which is 2nd lowest on record)

Most of October 2021's precipitation came from one big, and rather unusual storm on the 23rd which we talked about a bit here.

 

This messy chart has 2021's precipitation so far for 9 Canadian cities. Calgary, Regina and Winnipeg are all really close at around 325mm. Vancouver, Toronto, Ottawa and Montréal are all 600mm~720mm. St. John's is way up above 1,100mm. Edmonton is down at the bottom.


Snow

And October 2021 was snowfree. This chart is a history of early snowfalls, for August-October. 

The last time that the airport made it to Halloween with no recorded snow was 2015. Before that was 2011, 2008, 2005, and before that all the way back to 1988.

Blatchford hasn't had snow readings since 2007. But at the airport the average snow for October is 9cm, and the average date of the first snow is October 5th.


November

In November we still average 18 days with Highs above freezing, but we start seeing Lows of -10°C and -15°C. We haven't hit -20°C in November since 2015, and let's not talk about the -29.8°C in 2014. November averages 20cm of snow, which is pretty typical for our winter months.