Although July finished off with a cold snap, this was offset by the very hot start making it a warmer than average month. Overall it was about a degree above average, but this was all because of the daily low temperatures that were 2 degrees above average, as the daily highs were very close to average.
A dramatic change in temperature occurred when a cold front moved through the area on the 19th bringing with it winds that caused a lot of damage from southern Ontario to Quebec. From 5:15 pm to 5:30 pm that day, the temperature dropped almost 9.5 degrees, this was the largest 15 minute temperature drop in the 15 year history of the UW weather station. Also interesting is that it only got down to 24.7 C the morning of the 19th. This would make it the one of the warmest nights on record, however as the temperature dropped that evening the official low for the day was less than 20. I will have to do some more digging to find the actual warmest night on record.
There were not that many days with precipitation in July, but when it happened, it really came down with 4 days over 30 mm resulting to a total of 173.1 mm for the month. This was almost double the average of 92.9 mm and the most since 1991 (when we had 182.6 mm).
This wet month puts the total for the year at 741.9 mm, well above the average for the end of July of 509.0 mm. This also makes it the second wettest first seven month of the year since records began in the region almost 100 years ago, only behind 1947 at 764.5 mm.
Summary for July 2013:
Maximum Temperature 32.6°C
Minimum Temperature 8.7°C
Average Daily High Temperature 26.1°C (Long term average 26.0°C)
Average Daily Low Temperature 15.9°C (Long term average 13.8°C)
Total Precipitation 172.1 mm (Long term average 92.9 mm)
(Long term averages based on 1971-2000 data for the Waterloo Wellington Airport)