September 2019 Summary

Another hot and dry September

I always say there is never a sure thing when it comes to the weather, but for the past 20 years a really good bet has been that September will be warmer than average.  Although this was the least warm September in the past 6 years, it was still 2 degrees above the average. 

Apart from 3 days late in the month when the temperature was above 25°C there really weren’t any extended heat waves, just a lot of days a little warmer than average.  OK I know I’m really digging deep for this one, but the lowest temperature during the month was 5.7°C and I was not able to find another September with a higher minimum temperature in the 100 years of weather records in the region (the closest was 5.4°C in 2015).

A few storms during the first half of the month kept us moderately wet, but a week of no rain and only a few storms in the second half led to a total of just 44.8 mm, which is about half the average of 87.8 mm.  The last time we had a wetter than average September was back in 2014, in fact from 2010-2014 we had a streak of wetter than average Septembers and since then they have all been drier.

With this dry month, the total for the year of 660.8 mm is now slightly below the average of 683.5 mm for this time of year.

Summary for September 2019:

Maximum Temperature 29.0°C

Minimum Temperature 5.7°C

Average Daily High Temperature 22.2°C (Long term average 20.4°C)

Average Daily Low Temperature 10.8°C (Long term average 8.6°C)

Total Precipitation 44.8 mm (Long term average 87.8 mm)

(Long term averages based on 1981-2010 data for the Waterloo-Wellington Airport)

August 2019 Summary

A hot August with average precipitation

In contrast to last year when the overall August temperature was almost 3 degrees above average, this year it was only 0.9 degree higher than average, putting it just into the above average range.  There was a definite shift part way through the month with the average temperature dropping a degree before and after the 21st, this shift can be clearly seen in the graphs.

About three quarters of the month’s precipitation came during 5 very wet days during the middle of the month, with the rest of the month being relatively dry.  The total of 89.4 mm was not enough above the average of 83.9 mm to put it outside of the average range for August.

The total precipitation we have seen so far in 2019 of 616.0 mm is still above the average of 596.0 mm for this time of year.


Summary for August 2019:
Maximum Temperature 29.8°C
Minimum Temperature 7.6°C
Average Daily High Temperature 25.9°C (Long term average 24.8°C)
Average Daily Low Temperature 13.5°C (Long term average 12.9°C)
Total Precipitation 89.4 mm (Long term average 83.9 mm)


(Long term averages based on 1981-2010 data for the Waterloo-Wellington Airport)

July 2019 Summary

A very hot and dry July

Although it wasn’t the hottest month ever (as has been reported for the global temperature), locally it was still over 2 degrees higher than average making the hottest month since July of 2012.  It was also the first above average month we have seen this year, as well the 9 days over 30°C was well above the average of only 3.5 days.

July was very dry with only 39.8 mm of rain which is less than half the average of 98.6 mm.  It also wasn’t spread out very well with over half of the total coming on the 17th, leaving only a little bit more to be spread over the rest of the month.

This dry month brought the total precipitation for the year of 526.6 mm back down closer the average of 509.0 mm.


Summary for July 2019:
Maximum Temperature 33.3°C
Minimum Temperature 10.4°C
Average Daily High Temperature 28.7°C (Long term average 26.0°C)
Average Daily Low Temperature 15.8°C (Long term average 14.0°C)
Total Precipitation 39.8 mm (Long term average 98.6 mm)

(Long term averages based on 1981-2010 data for the Waterloo-Wellington Airport)

June 2019 Summary

A very average June for both temperature and precipitation

In contrast to the last few years when there were lots of June days at or above 30°C (8 in 2016, 3 in 2017, and 4 in 2018), there was only one day this past June when it just barely made it to 30°C.  Despite this, there were enough warm days to put the overall temperature at almost exactly at the average (well 0.04 degrees above, but let’s say that rounds off to 0.0).   The also marks the first month this year that was not at least a little bit below average.

There was also a pretty regular series of moderate storms that came through during the month to keep the precipitation within the average range, although the total precipitation of 73.6 mm was below the long term 1981-2010 average of 82.4 mm.

For the first half of the year, the total precipitation we have seen of 486.8 mm is not that far above what we would expect for the halfway mark of 416.1 mm.

Summary for June 2019:

Maximum Temperature 30.0°C

Minimum Temperature 4.4°C

Average Daily High Temperature 23.6°C (Long term average 23.6°C)

Average Daily Low Temperature 11.6°C (Long term average 11.5°C)

Total Precipitation 73.6 mm (Long term average 82.4 mm)

(Long term averages based on 1981-2010 data for the Waterloo-Wellington Airport)

May 2019 Summary

A cooler May (but still barely average) with lots of rain

Last year after a cold April, May came back extremely warm, this year not so much.  The first half of the month was about a full degree below average, but the second half was warm enough to put us at 0.7 degrees less than average overall for the month.  This was just warm enough to keep it within the average range.

Also, unlike last year when we had 3 days above 30°C, the highest temperature for May this year was only 27.5°C.  You have to go back 10 years to find a lower highest temperature of the month.

On the other end of the termometer, we didn’t have a temperature below zero during May, so that means the last one occurred on April 29.  This is on the early end of the range of Apr 26 to May 23 for the last below zero temperature we have seen in 20+ years of data at the UW Weather Station.

It was a wet month with a pretty good soaking every week or so that put the total of 103.4 mm well above the average of 82.3 mm.  With 4 wetter than average months in a row, it is not surprising that the total for the year is now 413.2 mm is now much higher than the 340.2 mm that we would expect for this time of the year.

Summary for May 2019:

Maximum Temperature 27.5°C

Minimum Temperature 0.5°C

Average Daily High Temperature 17.4°C (Long term average 18.5°C)

Average Daily Low Temperature 6.1°C (Long term average 6.4°C)

Total Precipitation 103.4 mm (Long term average 82.3 mm)

(Long term averages based on 1981-2010 data for the Waterloo-Wellington Airport)