Monday, August 1, 2011

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)


Kuhny said...

On the last day of the mid-month spell of 30 C days, the average high at the airport was very nearly 30 C. Note the last time we did have a month with an average high temperature of 30.0 C or more was July 1955.

TWN said...

For Rob Kuhn,

Pearson had a mean temp of 24.4 in July, this is even hotter than 1955 at 24.3. Has there been a year with a warmer month before that?

Kuhny said...

Nope. The July 1955 average max temp of 31.0 at Pearson was higher than this July's 30.1. But the night time lows this year were considerably higher at Pearson airport - hence the higher mean temperature. I suspect some of that may be due to increased urbanization around the airport there.

Anonymous said...

many storms appear on radar as heading this way but seem to break up or go south before reaching KW. Is there a reason for this or is it my perception?

Anonymous said...

Are we going to see a summary for August by any chance? Love reading those!

Anonymous said...

Will a summary for August appear? I always enjoy reviewing them.

Anonymous said...

August summary?