2025 Summary

E.D. Soulis Memorial Weather Station at the University of Waterloo Annual Summary - 2025

The biggest weather story of 2025 again was the temperature, not overall for the year, just part of it.  These were the months of March, April, June, and July that were all more than 2 degrees above average.  The overall temperature for the 5 months between March and July were the second warmest in the history of the region, where records go back over 100 years.  These months also included the third highest temperature ever recorded in the 28 year history of the Soulis Memorial Weather Station.  The overall average temperature for 2025 was half a degree above average, which tied it with 2001 as the 15th warmest year in the region’s history.

The year started out very cold with some of the most frigid days we have seen in a few years.  The temperature went below -20°C for three days in a row, which had not happened since January of 2022.  The cold temperatures of January continued into the first 3 weeks of February, before we finally saw some warmer temperatures with six days of highs above zero in the last week.  Looking at the entire meteorological winter (December-January-February), the average temperature was a little more than one degree below average, making it the coldest winter since 2014-15.

Both March and April were more than 2 degrees above average, with April coming in as the warmest since 2017 and the third warmest in the history of the station.  A warmer first half May was offset by a cooler second half, leading to an overall temperature that was right on the average for the month.  

With one of the most extreme June heat waves we have experienced, it is not surprising that it was the sixth hottest June in the history of weather records for the region. While the high of 35.0°C on June 24th was the third highest temperature ever recorded at the station.

There were multiple heat waves throughout July and 18 days above 30 degrees, the overall temperature was an amazing two and half degrees above average.  This resulted in the month being the fourth hottest in the history of weather records in the region and the hottest since 1955.  August started out very warm, but this ended on the 16th with the temperature going back closer to average for a week and then the month ending with a week of below average temperatures.

Overall the meteorological summer (June-July-August) was very hot, the temperature was over one and half degrees above average, this made it the hottest since 1955 and the fourth warmest in the history of weather records in the region. 

Although there wasn’t a day above 30°C in September or October, there were still lots of very warm days resulting in an overall temperature that was one degree above average for both months.  The temperature first went below zero at 4:30 am on October 9, about 5 days later than the average.  This year the growing season was 153 days, less than the average of 160 days.

It cooled off a bit at the end of the year starting in November followed by the first half of the December that had many daily lows more than ten degrees below average.  The overall temperature was a bit more than 3 degrees below average, making it the second coldest December in the last 20 years.

The first three months of the year experienced pretty close to average precipitation, followed by a very wet April.  This included April 3rd which was one of the wettest days in the history of the region, overnight the precipitation started as a wintery mix before changing over to steady rain that peaked in the late morning.  The total for the day was 78.8 mm, the wettest single day since Jan 11, 2020.  Then the next few months were all just a little above average followed by a dry August.

Then with only 10 mm of rain in the first 20 days of the month, it was looking like it could have been one of the driest Septembers on record.  But then we received 44.8 mm of rain on the 21st, which was the fourth wettest September day in the history of the station.  The total for the month ended a bit above average followed by a dry October.  After a close to average November, the precipitation for December was going along mostly average before the almost 50 mm on the 28th that resulted in a wet month.

The overall precipitation for the year was 943.2 mm, above the average of 869.6 mm.

The calendar year of 2025 had many snowy months.  The 68.5 cm in January was 50% more than the average, followed by the 77.5 cm in February that was more than double the average.  The overall total for the 2024/25 snowfall season was 194.0 cm, compared to the average of a typical season of 159.7 cm.

The next snowfall season started with November coming in at 59 cm which was the second highest for the month in the region.  December had a bit less at 54.5 cm of snow, but still much more than the average of 30.7 cm for the month.  Thus in the first 2 months of the 2025/26 snowfall season there was already over half of the average total.

Frank Seglenieks
E.D. Soulis Memorial Weather Station Coordinator

Summary for 2025 (averages from 1998-2024 data for Soulis Memorial Weather Station):

Average Daily High Temperature: 13.76°C (average 12.63ºC)
Average Daily Low Temperature: 252°C  (average 2.62ºC)
Total Precipitation: 943.2 mm (average 870.7 mm) 

Extremes for 2025 (all time Soulis Memorial Weather Station extreme in brackets):

Highest temperature:
35.0°C Jun 25 8:30 pm (35.7 °C July 21, 2011 3:00 pm)

Highest humidex:
45.9 Jun 22 8:15 pm (47.6 July 17, 2013 5:00 pm)

Lowest temperature:
-23.1°C Dec 8 7:00 am (-35.5 °C Feb 16, 2015 7:00 am)

Lowest windchill:
-35.0 Jan 21 6:45 am (-47.3 Feb 15, 2015 6:15 am)

Greatest temperature drop in 15 minutes:
-5.3°C Jun 5 2:00 am (-9.5 °C July 19, 2013 5:00 pm)

Greatest temperature drop in 60 minutes:
-8.8°C Jun 25 4:15 - 5:15 am (-11.8 °C July 19, 2013 4:45-5:45 pm)

Greatest temperature rise in 15 minutes:
6.4°C Jan 24 8:45 am (8.6 °C Jan 2, 2001 6:15 am)

Greatest temperature rise in 60 minutes:
8.4°C Jan 24 8:15 - 9:15 am (12.2 °C Jan 2, 2001 4:45-5:45 am)

Highest precipitation in 15 minutes:
14.6 mm Jun 28 7:00-7:15 am (24.8 mm Jul 10, 2020 6:45-7:00 pm)

Highest precipitation in 60 minutes:
29.4 mm Apr 3 10:00-11:00 am (57.4 mm Aug 2, 2014 2:30-3:30 pm)

Highest Precipitation in 1 day:
78.8 mm Apr 3 (88.0 mm Sep 22, 2021) 

Highest 15 minute average wind speed:
29.9 km/h Feb 26 1:45 pm (44.6 km/h Mar 9, 2002 6:30 pm)

Highest wind gust (only available since 2015):
38.5 km/h Apr 30 6:45 pm (44.4 km/h Apr 13, 2015 2:30 pm)

Last time the temperature went below 0 before the summer:
May 9 4:45 am (Has ranged between Apr 26 - May 23)

First time the temperature went below 0 after the summer:
Oct 9 4:30 am (Has ranged between Sep 19 - Oct 29)

Length of frost-free season
153 Days (Has ranged between 129-186 days)

Highest daily low temperature:
23.8°C Jun 24 (25.3 °C Aug 1, 2006)

Lowest daily high temperature:
-12.4°C Jan 22 (-20.6 °C Feb 15, 2015)

Largest daily temperature range:
24.5°C May 12 (29.6 °C Feb 19, 2007)

Smallest daily temperature range:
2.30°C Dec 30 (0.45 °C Dec 7, 2005)