December 2020 Summary

 A warm December with average precipitation

With the only cold streak lasting just a few days in the middle of the month, it is not surprising that overall temperature was 1.7 degrees warmer than average.  This now makes 6 of the last 7 Decembers that have been warmer than average 

There wasn’t much precipitation in the first 3 weeks of the month, but a wet last week put the total of 64.4 mm close to the average of 71.2 mm.

December saw 44.5 cm of snow, a little more than the average of 37.2 cm for the month. 

Summary for December 2020:

Maximum Temperature 9.3°C
Minimum Temperature -11.4°C
Average Daily High Temperature 1.5°C (Long term average 0.2°C)
Average Daily Low Temperature -4.6°C (Long term average -6.8°C)
Total Precipitation 64.4 mm (Long term average 71.2 mm)

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

November 2020 Summary

 A very warm November that was a bit drier than average

What a difference a year makes, last year was the coldest November in almost 25 years and this year it was the warmest in almost 10 years.  Overall, it was more than 3 degrees above average, almost 6 degrees higher than last year, and the 5^th warmest November in the over 100 years of weather records in the region.

This was a result of a week of record breaking temperatures at the start of the month.  The records that fell include: the high on the 9^th of 23.9°C was the second highest November temperature for the region (highest was 25.0°C on Nov. 1, 1950), we had 4 days in a row over 20°C which was the longest such streak in November, and finally the 8 days in a row above 15°C beat the previous longest streak of 7 days.

There were only a few days with any significant precipitation scattered throughout the month, which resulted in a total of 61.4 mm, putting it just below the average range.  The total precipitation of 886.5 mm is above the average for this time of year of 832.9 mm, and with only one more month to go in the year, unless December is very extreme we will probably end year with close to average.

The total snowfall of 22.5 cm was quite a bit more than the average of 13 cm for November.

Summary for November 2020:
Maximum Temperature 23.9°C
Minimum Temperature -6.5°C
Average Daily High Temperature 10.1°C (Long term average 6.3°C)
Average Daily Low Temperature 1.2°C (Long term average -1.4°C)
Total Precipitation 61.4 mm (Long term average 87.1 mm)

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

October 2020 Summary

An average October for both temperature and precipitation

Although this was the coldest October in over 10 years, it was still only 0.1 degrees below the average, putting it well within the average range.  This is because October has been one of the most above average months in the past decade, after both September and August.

Looking at the graph, you can see just how much the high of 24.2°C on the 23rd was a blip compared to the rest of the month.  As the average temperature goes down a lot between the beginning and end of the month, it is rare that the highest temperature would occur that late.  In fact, that was the warmest day in the second half of October since 1968 when it was 24.4°C on the 17th.

The month started off with pretty average precipitation, got a bit wetter in the middle an ended off dry.  The total was 71.4 mm, a bit above the average of 67.4 mm and just within the average range for the month.

Random fact: we have only had one October that was drier than average in the past 10 years.

This slightly above average month resulted in the total precipitation since January (825.1 mm) staying above the average for this time of year (750.6 mm).

Summary for October 2020:
Maximum Temperature 24.2°C
Minimum Temperature -6.5°C
Average Daily High Temperature 12.6°C (Long term average 13.5°C)
Average Daily Low Temperature 3.6°C (Long term average 2.9°C)
Total Precipitation 71.4 mm (Long term average 67.4 mm)

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

September 2020 Summary

Another warm September with average precipitation

I know it seems that every September I talk about how consistently warm the month is compared to the other months of the year.  Well it turns out it is not just my imagination, here is a map (albeit for the US) of which month has warmed the most in the last 30 years:

https://twitter.com/Climatologist49/status/1307864627452149760

and you can see that around the Great Lakes that month is consistently September.

Although we saw some cooler temperatures, the pattern continued as the overall temperature was 0.8 degrees above average.  There were some cold nights during the month, but these were offset by almost a week that got to the mid-20s at the end of the month.

One of those cold nights happened on the 19th when the temperature actually went below zero for the first time since the spring.  This is the earliest it has happened in the 22 year history of the weather station and the coldest September temperature since September 30, 1993.

And now a riddle: What is wet on both ends and dry in the middle? 

Answer: September 2020.  

We saw 28.6 mm in the first 3 days of the month and 36.2 mm in the last 3 days, and only 22.4 mm in the other 24 days.  This included a stretch of 2 weeks with no rain at all between the 14th and 27th.  The total of 87.2 mm was just a little below the average of 87.8 mm for the month.

For the year so far, we have seen 753.7 mm of precipitation which is above the average of 683.5 mm for this time of year.

Summary for September 2020:
Maximum Temperature 27.9°C
Minimum Temperature -1.4°C
Average Daily High Temperature 21.4°C (Long term average 20.4°C)
Average Daily Low Temperature 9.2°C (Long term average 8.6°C)
Total Precipitation 87.8 mm (Long term average 87.8 mm)

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

August 2020 Summary

A hot August that was both wet but also dry

Although it wasn’t as hot as July, August did continue the pattern of hot summer temperatures.  The heat was consistent with the longest stretch of colder than average temperatures being only 3 days.  Overall it was 1.5 degrees above average, contributing to that were 6 days above 30°C, a lot more than the 2 we usually see.

Why did the headline say it was both wet and dry?  In the first three days of the month we saw 72.2 mm of precipitation (more than the average total for 5 months of the year) but then only 11.2 mm the rest of the month.  So both wet and dry.  The total precipitation for the month of 83.4 mm was just a smidge lower than the average of 83.9 mm.

The total precipitation we have seen so far in 2020 of 666.5 mm is still above the average of 596.0 mm for this time of year.

Summary for August 2020:
Maximum Temperature 31.6°C
Minimum Temperature 7.9°C
Average Daily High Temperature 26.6°C (Long term average 24.8°C)
Average Daily Low Temperature 14.2°C (Long term average 12.9°C)
Total Precipitation 83.4 mm (Long term average 83.9 mm)

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