Sunday, February 4, 2018

January 2017 Summary


A cold and wet January

The start of the month was very cold, as well as some days in the low minus 20s, we had a streak of 12 days (going back into 2017) where the temperature never went above -8°C.  This is the second longest streak like this, only surpassed by 1961 when there were 15 and just a little longer than in 1979 when we had 11.

We then experienced many temperature oscillations with a few days above zero, followed by a few below, and so on.  In fact the temperature passed through zero a total of 6 times leading to some mixed precipitation making for some difficult driving and walking conditions.

However, the warmer temperatures couldn’t make up for those really cold temperatures at the beginning of the month leading to an overall temperature that was a little more than a degree below average.

The total precipitation that fell was 73.3 mm, enough above the average of the 65.2 mm to put it into the above average range.  As far as snowfall, we had 28 cm less than the average of 43.7 cm for the month, while the total so far this season is 66 cm compared to the average of 95.3 cm for this point in the snowfall season.


Summary for January 2018:
Maximum Temperature 11.3°C
Minimum Temperature -28.6°C
Average Daily High Temperature -2.7°C (Long term average -2.6°C)
Average Daily Low Temperature -12.5°C (Long term average -10.3°C)
Total Precipitation 73.3 mm (Long term average 65.2 mm)

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



Wednesday, January 10, 2018

2017 Summary

University of Waterloo Weather Station Annual Summary - 2017

There weren’t that many individual notable moments during 2017, but what was notable was how many times there were consecutive days of interesting weather leading me to call this the “year of streaks”.  There is no official measure of streaks so it can’t be said definitively that it was the most ever, but it seemed like there were lots of them.

It started in January when we saw 12 days in a row that went over 0 degrees, this is something that we had not seen since 1944.  There were also a lot of days were the sun did not make an appearance, leading me to invent something called “dreary” days and there were more of these in January then in any other January in the history of the UW Weather Station.

The next streak came in February with another 12 days in a row above 0, something that hasn’t happened in the over 100 years of weather data in the region and leading to it being the warmest February we have seen.  Also notable was the high of 15.1°C on the 23rd which was the highest February temperature we have ever seen in the region, while in second place was the 15.0°C which happened the day before.

Then for only the 5th time in 100 years March was colder then February followed by a warm April and the see saw continued with a cold May.  The summer was generally very close to average with not a lot of really hot or cold days.

It wasn’t till the end of September that we saw the longest heat wave of the “summer”.  The most significant streak was the 15 days above 25°C between the 12th and the 26th, which is something we have never seen before in September. 

In October there were 12 days where the temperature was over 20°C, we haven’t seen that many since October 1971.  But the most significant day was the 22nd when the temperature topped out at 25°C, this was tied with 1947 as the latest day of the year with a temperature above 25°C.

However, the cold temperatures came back with a vengeance in December, the coldest one since 2000, that featured a streak of very cold days at the end that went into the next year.  It was so cold that during the last 6 days of the month, the daily high temperatures didn’t even get above the average daily low temperatures for those days.

Overall the year was 1.1 degrees above average, making it the tenth warmest we have seen in the region.

The first half of the year was the second wettest on record, fueled by a very wet April followed by an even wetter May.  The rest of the year was more or less average with the final total of 988.6 mm coming in just within the above average range.



Summary for 2017:
Average Daily High Temperature: 13.09°C (average 12.05ºC)
Average Daily Low Temperature: 3.20°C  (average 1.94ºC)
Total Precipitation: 988.6 mm (average 916.3 mm)


(averages are calculated from 1981-2010 data for the Waterloo-Wellington Airport)

Click on the image below to see the temperature chart:

Click on the image below to see the precipitation chart:

Tuesday, January 2, 2018

December 2017 Summary


A cold and dry December

For almost the entire first week, December was pretty warm with some double digit temperatures, however things then got somewhat colder before getting really cold.  So cold that during the last 6 days of the month, the daily high temperatures didn’t even get above the average daily low temperatures for those days.

Overall it was a bit more than 3 degrees below average making it the coldest December since 2000, while the cold streak at the end of the month might turn out to be one of the longest we have seen in the history of records in the region (but more on that next month).

The colder temperatures meant that most of the snow that fell remained on the ground at the end of the month.  However, this might have masked the fact that we didn’t get that much precipitation during December with only 32.0 mm compared to the average of 71.2 mm.

As far as snowfall, we had 31 cm which was just a little less than the average of 37.2 cm for the month.

Summary for December 2017:
Maximum Temperature 10.6°C
Minimum Temperature -28.1°C
Average Daily High Temperature -2.3°C (Long term average 0.2°C)
Average Daily Low Temperature -10.8°C (Long term average -6.8°C)
Total Precipitation 32.0 mm (Long term average 71.2 mm)


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



Saturday, December 2, 2017

November 2017 Summary


An average November for both temperature and precipitation

After the warmth of the last two months we finally experienced some cooler temperatures.  Overall, November was about half a degree cooler than average, but still within the average range (the last time we saw a month that was in the below average range was April 2016).

However, if you take a look at the temperature graph you can see that the 10th and 11th really stand out as abnormally cold days.  The temperature went down suddenly for about 36 hours and then just as suddenly came back up.  In fact, if you took out those two days the month would have ended up being a bit above average.

Although the 66.2 mm of precipitation was well below the average of 87.1 mm this was just enough to put November into the average range.  So going into the final month of the year the total precipitation for the year is 956.6 mm which is above the average of 832.9 mm.  This also means that we are already above the average for the year of 916.3 mm, and would only need an average December to end up above average for 2017.


Summary for November 2017:
Maximum Temperature 15.8°C
Minimum Temperature -12.3°C
Average Daily High Temperature 6.2°C (Long term average 6.3°C)
Average Daily Low Temperature -2.3°C (Long term average -1.4°C)
Total Precipitation 66.2 mm (Long term average 87.1 mm)

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



Friday, November 3, 2017

October 2017 Summary


A very warm October with above average precipitation

Most of October was really warm and if it wasn’t for the cooler temperatures in the last week it might have been one for the record books.  As it was, the overall temperature was over 3.5 degrees above average making it the second warmest in almost 50 years (it was 5 degrees warmer than average in 2007).

We also saw 12 days in October where the temperature was over 20°C, we haven’t seen than many since October 1971.  But the most significant day was the 22nd when the temperature topped out at 25°C, this was tied with 1947 as the latest day of the year with a temperature above 25°C in the over 100 years of weather records in the region (just for the record it got up to 25.6°C that day in 1947).

As we have seen in each of the 20 years of weather data at the UW Weather Station, the first day that it went below zero occurred in October.  This year it first happened on the morning of October 26th, which is later than the recent average of the 13th.  The resulting length of the frost-free season was 170 days, a little longer than the recent average of 160 days.

The 77.0 mm of precipitation was just enough above the average of 67.4 mm to put the month in the above average range.  The total precipitation for the year is 890.4 mm is still well above the average of 750.6 mm.


Summary for October 2017:
Maximum Temperature 25.7°C
Minimum Temperature -1.2°C
Average Daily High Temperature 17.5°C (Long term average 13.5°C)
Average Daily Low Temperature 6.4°C (Long term average 2.9°C)
Total Precipitation 77.0 mm (Long term average 67.4 mm)

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