August 2025 Review & The Great Heatwave of August 2025

It's time for our big look back at Edmonton weather for August 2025. August has 31 days, but we're going to talk a lot about the final week. The word "unprecedented" gets thrown around a lot, but the end of August gave us a truly unprecedented heatwave.

August 2025's average High of 25.7°C was the 4th warmest on record. That's obviously hot, although recently 2022 got to 2nd spot with 26.6°C.

The average Low of 12.9°C was the 9th warmest. And again, that's warm. But it was actually below 2024, 2023 & 2022.





High Temperatures

August 2025 started warm, but then was maybe a little cool for a few weeks. 

But it ended with 8 straight 28°C Highs, 8 of which got to 30°C, and 4 of which got to 32°C. 

Overall there were 8 below-average Highs compared to 21 above-average, including 4 new records.

August averages around 10 25°C Highs, and 2025 had 19. 

That included 8 30°C Highs, when the average is around 1. 

The hottest was 33.3°C on the 27th. The coldest was 13.1°C on the 15th.





The Great Heatwave of August 2025

So what made this heatwave unique?

Our 30°C season can last from May-September, but it peaks in mid-July. From around June 22-August 18 is when we're most likely to reach 30°C. By August 25 we can still get there, but we're definitely out of the peak time.





Hot Days In-A-Row

The August heatwave gave us 6 30°C Highs in-a-row. That's the longest for this late in the year, and is 1 short of the all-time record set in July 2024 and July 2021. For late-August the previous record was only 3, and 2025 doubled that.

The August heatwave also gave us 4 32°C Highs in-a-row. That ties the all-time record from July 2021 and June 1961. And it also doubles the previous late-summer record, which was only 2 in-a-row.





Record Highs

We set 4 new record Highs in-a-row, from August 26th-29th. Those ranged from 32.2°C to 33.3°C, and were the 4th, 6th, 8th & 9th warmest temperatures ever recorded this late in the year.

Overall, 2025 now has 6 new record Highs. That's fewer that 2024's 11, but more than the 5 for 2021-2023. 

Just for the summer months of May-September, since 2021 we've set 29 new records, or about 20% of all of the days.





Hot Days So Far

The previous August record for 30°C days was 7, in 1967 & 1932. But 2025 sets a new record with 8. 

August 2025's 4 32°C days is also a new record, ahead of 3 in August 2008 & 1981. The 2 33°C days also tie 1922's record.

At the end of August, so far 2025 has had 14 30°C days. That ties 1964 for 3rd most ever recorded.

The only years with more? 2024 had 16, and 2021 had 17. (and with the forecast for September, we might catch them?)



Low Temperatures

And the Lows? Compared to the Highs they were a bit boring. For other recent heatwaves we had a lot of record-setting Lows, but August 2025 was warm without being flashy. 21 Highs were above-average and 10 were below.

August averages 4 Lows over 15°C, and 2025 had 7. But those were all early in the month. During the big heatwave dropped to around 12-14°C overnight.



The Horserace

How does the heatwave affect 2025's overall temperatures?

The mean temperature was already around top-20, and 1.5°C warmer than the 20th century average. 

August's hot week is visible here with the red line climbing upwards at the end, to around 13th warmest overall.



Warm & Cold Months

August 2025's average High of 25.7°C was 3.7°C warmer than the 20th century average, so it gets a medium orange bubble. But 2022 was warmer overall.

The average Low of 12.9°C was 3.3°C warmer also gets a medium orange bubble, similar to 2022-2024.



Across Canada

August 2025 another mostly above-average month across the country...except for Winnipeg. 

Kelowna & Edmonton were at the top, with Highs more than 3.7°C above their 20th century averages. 

Winnipeg was at the bottom, and -0.2°C below theirs.

One of the weird quirks of Edmonton's recent heatwaves is that this is the 2nd summer in-a-row where we've had as many (or even more) 30°C days than Winnipeg.



Precipitation

August averages 52mm of precipitation, which is our 3rd highest month.

In 2025 Blatchford was down at 28mm, Stony Plain got 44mm, the airport got 61mm, and Campsie (100km NW) got up to 114mm.

The big difference between the stations was the Blatchford's biggest day was only 11mm. The airport had 2 days around 15mm, and Campsie had 3 over 20mm.

By the end of August we average around 345mm of precipitation for the year (about 80% of our yearly total).

The airport and Campsie are right around average, while Stony Plain is at 266mm, and Blatchford is down at 248mm.



Precipitation Across Canada

These are the precipitation totals for 2025 across the country. Quebec City is still way out ahead with over 800mm. Montréal, St. John's & Halifax are over 600mm. Calgary is at 423mm, while Edmonton and the other prairie cities (also Kelowna & Victoria) are below 250mm.

Across the country the biggest August storms were: 

• Halifax & Vancouver over 40mm 
• Ottawa around 35mm 
• Quebec City, Toronto & St. John's around 25mm

September

For September we average 11 days at 20°C, including 3 at 25°C. And 2024 & 2022 both started with heatwaves.

For Lows, about half of the time September is frost-free, but right now our last September frost was 2019.

July 2025 Review

It's time for our big look back at July 2025 weather in Edmonton. Was it unseasonably cold? Kind of, but also not really? Let's take a look...

The general consensus seems to be that July 2025 was pretty cool. 

The average High of 23.9°C was our 52nd warmest on record, and above 2023 & 2020. 

The average Low of 12°C was our 49th warmest, and the coldest since 2019. 

So it was cool, but not particularly cold.





High Temperatures

July started and ended warm, but was a little cool in the middle. We only had 13 Highs above the 30-year average, compared to 18 below. 

The hottest was 31.9°C on the 2nd & 8th. The coldest was 16.3°C, which was July 21st's 5th coldest High on record.

July averages 12 25°C Highs, and 2025 had 12.

 

And it averages 3 30°C Highs, and 2025 got 3. 

The coldest High was 16.3°C on the 21st, but 2023, 2022 & 2021 all had Highs below 15°C.





Hot Days So Far

By the end of July we've had 62 20°C Highs. That's around average, and more than 2024, 2022, 2020, 2019. 

We've had 25 Highs reach 25°C - less than 2023, 2021 & 2018, but more than a lot of years.

July 31st was our 6th 30°C High of the year, so far.

This is the 5th summer in-a-row (2021-2025) to get to 6 of them. That's only happened once before, in 1932-1936.



Low Temperatures

July's Lows were pretty chilly, with only 12 above-average and 19 below.

And 4 of those were the coldest in at least 30 years. The 15th's 5.6°C and 23rd's 6.1°C were both bottom-10 Lows for those days.

Our range of July Lows is pretty narrow, usually between 5-20°C.

2025 had 8 cool Lows between 5-10°C, when the average is only 4.



Warm & Cold Months

July 2025 was cooler than recent years, but still warmer than the 20th century average, so it gets another small orange bubble.

The average High of 23.9°C was 0.6°C warmer than the 20th century average, and the Low of 12°C was 1°C warmer.



Across Canada

July 2025 was not warm in Edmonton, but it was actually cool in Calgary, Saskatoon & Regina, with Highs around 2°C below their 20th century averages. The rest of the country's Highs were around 2°C warmer than theirs.

For 30°C days so far this summer central Canada is a little above average, while Saskatoon & Regina are pretty low.



Precipitation

July is typically our rainiest month, averaging 90mm.

In 2025 the airport got up to 102mm, while the other stations were below 40mm.

The big difference was that the airport got a 20mm storm on the 6th, and 17mm storms on the 19th & 20th.

Blatchford's biggest day was only 12.7mm on the 19th.

By the end of July we average around 290mm of precipitation for the year.

The airport is right on average, and the other stations are down around 230mm.

These are the precipitation totals for 2025 across the country.

Quebec City is at the top with 750mm, which is their 20th most on record.

Calgary's 375mm is well ahead of Edmonton's 220mm, and is their 17th most.

And Winnipeg's 126mm is another low year for them.

Across the country the biggest July storms were:

• Montréal with 81.6mm on the 13th
• Toronto with 48mm on the 20th
• Quebec City with a whole bunch (6) ~30mm days.

August

For August on average we have 25 Highs which reach 20°C, including ~10 above 25°C. About half of the time August hits 30°C.

Most Lows are 10~15°C, but half of the time August will have a night below 5°C.

And August is our 3rd rainiest month averaging 52mm.

June 2025 Review

It's time for our big look back at June 2025 weather in Edmonton. It was a pretty unremarkable month, although sometimes that's not a bad thing...

June 2025's average High of 21.6°C was our 46th warmest June on record, and the average Low of 10°C was our 36th warmest. Those are both below the recent averages of 22.2°C and 11.1°C.





High Temperatures

June 2025 had 18 above-average Highs and 12 below-average. But they were all comfortably within our typical range, and nothing was particularly hot or cold.

June 2025 didn't get to 30°C, but the only recent Junes to get there were 2023 & 2021, and before that 2015.

June averages 5 25°C Highs, and 2025 had 6. It averages 18 20°C Highs, and 2025 got to 20.

And it averages 2 Highs below 15°C, and 2025 had 1, with 14.5°C on the 23rd.





Hot Days

By the end of June we average 35 20°C Highs, and 2025 is just a bit above that with 38.

Our recent average for 25°C Highs is around 11 (although the range is from 2 in 2022 to 26 in 2023), and 2025 has 13 so far.



Low Temperatures

June 2025 had 15 above-average Lows, and 15 below-average. None of the warm Lows were particularly warm, but June 22nd's 3.1°C and June 24th's 3.4°C were the coldest in 30 years.

On average June gets 1 Low below 5°C, and 2025 had 2. June also averages 2 Lows above 15°C, and 2025 had 1, with June 30th's 15.3°C.



Warm & Cold Months

June 2025 was cooler than recent years, but still warmer than the 20th century average, so it gets a small orange bubble here.

The average High of 21.5°C was 0.8°C warmer than the 20th century average, and the Low of 10°C was 1.3°C warmer.



Across Canada

Across the country the Highs for March through June have all been warmer than the 20th century average for all of these Stations. 

For June St. John's was the most above-average, at 4.9°C above their average, followed by Kelowna at 2.7°C above theirs.



The Horserace

6 months into 2025, and so far it's a pretty warm year.

Overall it's Edmonton's 16th warmest year on record, at 1.3°C warmer than the 20th century average. The Highs are 21st warmest, and Lowest are 17th warmest.

Across the country January-June 2025 is Dawson City's 6th warmest and St. John's 7th warmest. Quebec City is at the bottom, with 2025 as its 68th warmest January-June.



Precipitation

In June we average 77mm of precipitation, and 2025 was pretty average. The airport got 82mm, Blatchford got 72mm, and Stony Plain got 64mm.

By the end of June we average around 203mm of precipitation for the year. In 2025 Blatchford is a little low with 183mm, the Airport has had 187mm, and Stony Plain had had 189mm.

These are the precipitation totals for 2025 so far across the country. 

St. John's and Quebec city are at the top around 540mm. All of the prairie cities, along with Victoria, are below 200mm.



Big Storms

Around Edmonton June's biggest storms were: 

• Campsie 17.1mm on June 14st
• Blatchford 17.8mm on June 14th 
• Stony Plain 29.4mm on June 19th 
• The Airport 32.9mm on June 19th

Across the country the biggest June storms were: 

• Charlottetown 53mm on June 7th 
• Calgary 48mm on June 21st 
• Moncton 32mm on June 7 
• Quebec City had 3 ~30mm storms.

July

For July, the average High is about 23.5°C. It has around 25 days reach 20°C, including about 10 at 25°C. 

 Most July's will get at least one 30°C day, but recently 2020, 2019 and 2016 didn't.

July is also usually our rainiest month, with an average of 90mm.