September 2025 Summary

A hot September that started out dry and then got wet

Although there wasn’t a day above 30°C in September, there were still lots of very warm days in the middle of the month, resulting in an overall temperature that was one degree above average.  But there was quite a contrast between the daily high temperatures (2.6 degrees above average) and the daily low temperatures (0.6 degrees below average).  In fact, the average daily high temperature of 24.6°C was the third highest for September in weather records in the region.

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 25+ year history of the E.D. Soulis memorial weather station.  This was followed by a few more wet days, resulting in a total for the month of 88.0 mm, which is above the average of 75.6 mm.

The total precipitation so far this year is now 697.8 mm, just a bit above the average of 683.5 mm.

Summary for September 2025:

Maximum Temperature 28.8°C
Minimum Temperature 3.8°C
Average Daily High Temperature 24.6°C (Long term average 22.0°C)
Average Daily Low Temperature 9.7°C (Long term average 10.3°C)
Total Precipitation 88.0 mm (Long term average 75.6 mm)

(Long term averages based on 1998-2024 data from the Soulis Memorial Weather Station at the University of Waterloo)

August 2025 Summary

A dry month with average temperature and the hottest summer in 70 years

The month 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.  All of this resulted in an overall temperature that was 0.3 degrees below the average, which is still within the average range.

August also started off very dry with less than 5 mm falling in the first half.  There were a few wetter days in the second half, but still the total only got up to 46.2 mm, which is well below the average of 66.5 mm.  This brought the total precipitation so far in 2025 (609.8 mm) back closer to the average (596.0 mm).  

As we are now past meteorological summer (June-July-August) we can say it was a very hot summer.  The temperature was over one and half degrees above average, this makes it the hottest since 1955 and the fourth warmest in the history of weather records in the region which go back to 1914.  There were 34 days above 30°C which is much more than average of 11.  While the total precipitation of 230.6 mm was just a bit above the average of 214.8 mm.

Summary for August 2025:

Maximum Temperature 32.6°C
Minimum Temperature 5.3°C
Average Daily High Temperature 25.9°C (Long term average 25.6°C)
Average Daily Low Temperature 13.3°C (Long term average 14.2°C)
Total Precipitation 46.2 mm (Long term average 66.5 mm)

(Long term averages based on 1998-2024 data from the Soulis Memorial Weather Station at the University of Waterloo)

July 2025 Summary

The hottest July in 70 years with average precipitation

With multiple heat waves throughout July and 18 days above 30 degrees, the average 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.  There was little relief from the warm temperatures as only a single day had a high that was below average.

After a wet first day of the month there was a week long dry spell.  After that, there were regular storms that came through resulting in a total precipitation of 98.4 mm.  This is above the average of 78.2 mm, but still within the average range.

With the last 6 months all being slightly wetter than average, the total precipitation so far in 2025 of 563.6 mm is getting even more above the average of 503.5 mm.  

Summary for August 2025:

Maximum Temperature 33.1°C
Minimum Temperature 9.6°C
Average Daily High Temperature 29.6°C (Long term average 25.6°C)
Average Daily Low Temperature 16.7°C (Long term average 14.8°C)
Total Precipitation 98.4 mm (Long term average 78.2 mm)

(Long term averages based on 1998-2024 data from the Soulis Memorial Weather Station at the University of Waterloo)

June 2025 Summary

June was very hot month along with average precipitation 

With one of the most extreme heat waves we have seen during June, it not surprising that it was the sixth hottest June in the history of weather records for the region that go back over 100 years.  Overall, it was a little over 2 degrees warmer than the average.

The high of 35.0°C on June 24th was the third highest temperature ever recorded for any month in the 25+ year history of the Soulis Memorial Weather Station at the University of Waterloo.  There were 5 days over 30°C, where on average we get 3 during June and on the other end, the low temperature of 2.4 °C on 2nd was the lowest June temperature since 1998.

The month saw a couple of long dry spells interrupted by a few very wet days, resulting in a total precipitation was 86.0 mm.  This is above the average of 70.1 mm, but still within the average range.

With another close to average month, the total precipitation we have seen in the first half of the year of 425.4 mm is not that far below the average total of 465.2 mm.

Summary for June 2025:

Maximum Temperature 35.0°C

Minimum Temperature 2.4°C

Average Daily High Temperature 27.0°C (Long term average 24.1°C)

Average Daily Low Temperature 13.8°C (Long term average 12.6°C)

Total Precipitation 86.0 mm (Long term average 70.1 mm)

(Long term averages based on 1998-2024 data from the Soulis Memorial Weather Station at the University of Waterloo)

May 2025 Summary

A very average month of May 

A warmer first half of the month was offset by a cooler second half, leading to an overall temperature that was right on the average for the month.  The temperature last went below zero on May 9, which is close to the average date in the history of the Soulis memorial weather station. 

There were a couple of wet days during the month, but nothing out of the ordinary.  The final total was 88.2 mm, the wettest for May since 2019, but still within the average range.  So far the total for the year is 379.2 mm, which is close to the average of 340.2 mm.

Summary for May 2025:

Maximum Temperature 28.0°C
Minimum Temperature -0.9°C
Average Daily High Temperature 18.9°C (Long term average 19.1°C)
Average Daily Low Temperature 7.5°C (Long term average 7.3°C)
Total Precipitation 88.2 mm (Long term average 73.8 mm)

(Long term averages based on 1998-2024 data from the Soulis Memorial Weather Station at the University of Waterloo)