July 2013 Summary

A hot month that was also the wettest July since 1991

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)

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June 2013 Summary

A soggy month with average temperatures and a very wet first half of 2013

It was going along as a slightly cool month, but around the official start of summer it warmed up to put the overall average at 0.66°C higher than the average. However, that is still a few hundredths of a degree less than the 0.7°C we use to define the start of the above average temperature range.

And how did we come up with 0.7°C? Well the method we use at the UW weather station is to take 30 years of average monthly temperatures, order them smallest to largest, then the bottom 10 define the below average range and the top 10 define the above average range. The middle 10 are of course what defines the average range. There are differences between the high and low temperatures and differences for each month, but we just simplify things and use the average value of 0.7°C for all months.

For precipitation, it was looking like a typical month until we got hit with the largest one day precipitation in over a year. On the 28th we received 43.8 mm, with 16.8 mm of that coming between 2:15 and 2:45 pm. However, as a result of the type of precipitation we get in the area during the summer, there were areas that likely had even more intense precipitation that caused many flooded streets and parking lots in the area.

The total for the month was 120.9 mm compared to an average of 80 mm. Although this is well above average, we only have to go back to 2010 to find a wetter June when we had 130.3 mm.

Now that we are halfway through the year, we can see how it stacks up: For temperature it was 0.43 C above average, nothing too significant there. However, the 568.8 mm of precipitation is the 4th wettest first 6 months of the year, only behind 1947 (624.8 mm), 2011 (602.0 mm), and 1953 (583.9 mm). Also quite a contrast to last year when we only had 316.3 mm.

Summary for June 2013:
Maximum Temperature 30.5°C
Minimum Temperature 5.5°C
Average Daily High Temperature 22.8°C (Long term average 23.6°C)
Average Daily Low Temperature 13.4°C (Long term average 11.3°C)
Total Precipitation 120.9 mm (Long term average 80.0 mm)
(Long term averages based on 1971-2000 data for the Waterloo Wellington Airport)

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Odd spread in the temperature forecast

Usually the Environment Canada and the Weather Network forecast only differ by one or maybe two degrees.  But as of Wednesday evening, the two agencies are quite far apart from each other in their predictions of the forecasted highs for the upcoming weekend.

Environment Canada has a high of 29 for Saturday and 30 from Sunday to Tuesday, however The Weather Network only has us going up to 26 for all of those days.

June 28 rainfall

We got some significant precipitation in the area on June 28th.  At the UW weather station we recorded 43.8 mm during the day, the most intense part occurred between 2:15 and 2:45 pm when 16.8 mm came down.

This translates to what is referred to as a 1 in 2 year rainfall, that is not something that normally result in the numerous flooded streets and parking lots in the region.  Thus it is probable that a storm of this nature had areas of more intense rain that caused the localized flooding.

Spring 2013 Summary

The very typical Spring for both temperature and precipitation

There were the usual temperature swings during this season that borders winter and summer, but it was never really hot or cold for a very long time. Overall it was just 0.2 degrees colder than average which puts it solidly in the average range.

After a slow start to the spring precipitation (it was dry until the first week of April), the rest of the season was wetter with the total coming in on the high end of the average
range.

Summary for Spring 2013:
Maximum Temperature 28.6 °C
Minimum Temperature -9.2 °C
Average Daily High Temperature 15.1 °C (Long term average 15.6 °C)
Average Daily Low Temperature 4.8 °C (Long term average 4.2 °C)
Total Precipitation 256.4 mm (Long term average 219.5 mm)

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

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