July 2011 Summary

**Note that as a result of an incident of vandalism at the UW weather station this month, the temperature used for this summary is based on data from the Waterloo-Wellington Airport**

The hottest July in over 50 years that was also very dry

Do I really have to tell anyone that it was hot this month? I guess the question was how hot it was historically. First off, it was over 2 degrees above average overall for the month with 11 days above 30 and an average daytime high of 29.4°C. I had to go back to 1955 to find a hotter July (which had a scorching daily average high of 32.2°C) and overall the month was tied for the 6th warmest that has ever been recorded in the area.

The 35.7°C on the 21st was the highest temperature we have seen since August 8th, 2001 when it was 36.5°C.

Going along with the hot weather was the lack of rain, up until the last couple of days of the month it looked like it might be the second driest ever recorded (it would have been hard to beat the paltry 1.8 mm recorded in 1916). However, a couple of storms right at the end of July got us up to 22.3 mm and as there will a lot of months around with around 20 mm, this year ended up as the 7th driest in the region since records began in 1914.

This dry month means that the total for the year (624.3 mm) is creeping slowly closer to the average (509.0 mm). It was the second wettest first 6 months of the year, but now it is only the 9th wettest first 7 months of the year.

Summary for July 2011:
Maximum Temperature 35.7°C
Minimum Temperature 6.9°C
Average Daily High Temperature 29.4°C (Long term average 26.0°C)
Average Daily Low Temperature 14.9°C (Long term average 13.8°C)
Total Precipitation 23.2 mm (Long term average 92.9 mm)

(Long term averages based on 1971-2000 data for the Waterloo Wellington Airport)