Sunday, October 1, 2017

September 2017 Summary

Some historical temperatures during a dry September 

Well that was quite an end to September with the longest heat wave of the “summer” and some historical temperatures.  The most significant streak was the 15 days above 25°C between the 12th and the 26th, that is something we have never seen before in September during the 100+ years of weather records in the region (the previous record was 13 such days back in 1947).

Some other notable events were the 5 days in a row above 30°C, which is something we have only seen a few times, the last was back in 1952.  Finally, the high temperature on the 24th of 32.2°C was the highest seen that late in the year since September 24, 1931 when it was 32.8°C.

Not surprisingly, the overall temperature was almost 3 degrees above average, what might be surprising is that this is colder than the last 2 years although they didn’t have the extreme highs we saw this year.  It is also useful to remember that this year the month started off cool during the first week.

But since I have you here can we talk a bit about recent Septembers?  Fun fact: no other month has seen more consistently above average temperatures.  In the past 20 years of data at the UW weather station, there has not been one in the below average range and only once was it even slightly below average (by 0.1 degrees in 2006).

The month was also very dry with only 38.0 mm of precipitation compared to the average of 87.8 mm, with half of the total coming during the first 4 days.  This dry month puts the total precipitation for the year at 813.4 mm, which is still well above, but a bit closer to the average of 683.5 mm than it was at the end of August.

Summary for September 2017:
Maximum Temperature 32.2°C
Minimum Temperature 3.8°C
Average Daily High Temperature 24.1°C (Long term average 20.4°C)
Average Daily Low Temperature 10.7°C (Long term average 8.6°C)
Total Precipitation 38.0 mm (Long term average 87.8 mm)

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

August 2017 Summary

An average August for both temperature and precipitation 

Although we didn’t see lots of really hot temperatures this month (only one day above 30°C), we also didn’t see lots of cold ones.  This resulted in the overall temperature being just 0.2 degrees below average, but this is still within the average range.

This may be surprising to some, but the fact is we have seen a string of warm months of August in recent years with this year’s overall temperature being the coolest since 2008.  In the 20 years of data at the UW Weather Station, only one August (2004) was cold enough to be in the below average range.  It was also a lot cooler than last year when we had 8 days over 30°C in August.

The month started out very wet, but with drier conditions in the last week the total precipitation of 93.6 mm was within the average range coming in a bit higher than the average for August of 83.9 mm.

The total precipitation for the year of 775.4 mm is well above the average of 596.0 mm.  For the last few months we have been in second in the “wettest year to date” category, however, there were lots of wet months of August in the past so we have dropped down to the sixth wettest year so far since records in the area began just over 100 years ago.

Summary for August 2017:
Maximum Temperature 30.7°C
Minimum Temperature 6.2°C
Average Daily High Temperature 24.5°C (Long term average 24.8°C)
Average Daily Low Temperature 12.9°C (Long term average 12.9°C)
Total Precipitation 93.6 mm (Long term average 83.9 mm)

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

Thursday, August 24, 2017

Solar eclipse 2017

These are my recollections of my trip down to the US to get on the line of totality during the solar eclipse on August 21, 2017.  As well as just experiencing the eclipse I also took along a temperature sensor to record the effects of the sun being blocked.

Just a bit on the logistics, I stayed in a small town called Glasgow, Kentucky the night before the eclipse and woke up early to drive to Bledsoe Creek State Park in Tennessee which is east of Nashville.  I was worried there might be some traffic, but it was open roads all the way.  I got there about an hour and half before the park opened and was car number 120 in line.  The park was mostly forested, but there was a hydro cut where most people set up their camps as there was a pretty good open view of the sky.

It was nice being somewhere that wasn't wall to wall people, but enough people to have a good group experience.  There were also a few people with very large telescopes, including one guy who had his connected to a computer screen so everyone could see a close up of the sun.

The day was really hot and sunny, with high temperatures of around 35C.  A few clouds appeared in the early afternoon, but just one covered the sun about an hour before totality, after that it was clear.

About 10 or 15 minutes before totality is when it started to get noticeably less bright, note I didn't say darker, but it started to feel not quite so hot and I could take off my sunglasses.  I think this was made all the more noticeable because it was so hot that day.

Once the moon's shadow actually passed over it of course became dark almost instantly, it wasn't pitch black but maybe about as dark as it is 15 minutes after a regular sunset.  Also interesting was the horizon which looked like sunset or sunrise, but instead of just in one part of the horizon it was all around.  Then everything went in reverse once the sun came back out.

Here is a video that I made just by putting a phone on the ground, it starts about a minute before totality and goes till about a minute after.  You can see how quickly it got dark and how the sky changed during the event (note the I'm standing out of the camera's view, I don't know the people who are actually seen in the video):

Something I didn't notice until I watched the videos was just how loud the cicadas got during the eclipse.  If you watch this "time-lapse" I made you can see both the reduction in the light as well as the background noise.  This one starts about 5 minutes before totality and each segment is about 1 minute apart:

Here is the graph of temperature during the eclipse in Tennessee, I kept one of the sensors in the sun (not the usual way to measure temperature I know) and one in the shade.  You can see that the sensor in the sun went down about 7C and the one in the shade got down to about the same temperature but started about a degree lower (the variation in temperature before 14:00 is probably just me setting everything up getting the sensor out of my car, as well the temperature looks like it was still going up when I left the park so I didn't get the entire rising limb of the temperature graph):

And closer to home, at the UW weather station there was understandably a lessor effect on the air temperature:


With the eclipse being 75% or so in the region, there was a large effect on the incoming solar radiation and the wind speed, as shown in the graphs below:

Overall it was a great experience and I recommend trying to get into the path of totality if you can make it.  The only downside was that after getting out of the park there was about 5 hours of bumper to bumper, stop and go traffic to get away from the totality line.  So my biggest advice for the eclipse in 2024 is that wherever you are, stay somewhere close and spend the night so you don't have to deal with the traffic.

Thursday, August 3, 2017

July 2017 Summary

A dry July with average temperature 

A pretty average month for temperature, although it was half a degree warmer than average overall, this is still within the average range.  It was also very consistent as there were only 2 individual days that were more than 5 degrees from the average (you can see in the graph that the measured temperature was within the green band most of the time)

The wet first half of the month couldn’t make up for the very dry last half (only 11 mm after the 17th).  The final total for July was 64.0 mm which is a lot lower than the average of 98.6 mm.

With this dry month, the total precipitation for the year of 681.1 mm is now a bit closer to the average of 509.0 mm.  However, it is still the second wettest year so far (still behind 1947).

Summary for July 2017:
Maximum Temperature 29.9°C
Minimum Temperature 10.8°C
Average Daily High Temperature 25.9°C (Long term average 26.0°C)
Average Daily Low Temperature 15.1°C (Long term average 14.0°C)
Total Precipitation 64.0 mm (Long term average 98.6 mm)

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

Friday, July 21, 2017

June 2017 Summary

A hot June with average precipitation

During June we saw a few hot days (3 over 30°C), some colder ones (3 less than 18°C) and a whole lot of average ones.  However, continuing the trend for the last few years the nighttime lows were much warmer putting the overall temperature just over 1 degree above average.

Although the last week was really wet, it was actually quite dry to start off the month.  So the rain at the end of the month only managed to get the total for the month of 77.8 mm close to but still a bit below the average of 82.4 mm.

Looking at the first half of the year, the total precipitation of 617.8 mm is the second wettest first 6 months of the year, only coming behind 1947 when there was 624.8 mm.

Summary for June 2017:
Maximum Temperature 31.2°C
Minimum Temperature 6.4°C
Average Daily High Temperature 24.1°C (Long term average 23.6°C)
Average Daily Low Temperature 13.1°C (Long term average 11.5°C)
Total Precipitation 77.8 mm (Long term average 82.4 mm)

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

Thursday, June 1, 2017

May 2017 Summary

A cool and very wet May

The see-saw monthly temperatures continued in May with much cooler temperatures than the warmth we saw in April.  With a very cold start to the month and only a couple days above 25°C, the final overall temperature was 0.6 degrees below average making it the coldest May since 2009.

But the bigger story was that it just wouldn’t stop raining (well actually it did for a week but that didn’t seem to matter).  The total of 146.2 mm was much more than the average of 82.3 m, this is a lot but not even in the top 5 for the history of measurements in the area.

However, the total for April and May of 270.6 mm was the third highest of all time and not that much behind the record of 286.0 mm back in 1916.  While the total so far for the year of 540 mm is not only well above the average of 340 mm, but is also just below the record wettest first five months of the year (541.6 mm in 2011).

Summary for May 2017:
Maximum Temperature 28.4°C
Minimum Temperature -0.7°C
Average Daily High Temperature 16.7°C (Long term average 18.5°C)
Average Daily Low Temperature 7.0°C (Long term average 6.4°C)
Total Precipitation 146.2 mm (Long term average 82.3 mm)

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

Wednesday, May 3, 2017

April 2017 Summary

A warm and wet April

We saw a bounce back in temperatures with April coming in at two and half degrees above average, this makes it the warmest since 2010.  It was a classic spring weather pattern with some spells of temperatures over 20°C mixed in with days in the single digits.

It was yet another wet month, the total precipitation of 124.4 mm was much more than the average of 74.5 mm, and it was spread out over the month with 5 days over 10 mm.  The total for the year of 393.8 mm is well above the average for the first 4 months of the year which is 264.4 mm.

Assuming the 1 cm of snow that fell in April is the end of the snowfall season, the total will end up at 126.0 cm coming in below the average of 159.7 cm.

Summary for April 2017:
Maximum Temperature 26.1°C
Minimum Temperature -1.4°C
Average Daily High Temperature 14.1°C (Long term average 11.5°C)
Average Daily Low Temperature 3.5°C (Long term average 0.8°C)
Total Precipitation 124.4 mm (Long term average 74.5 mm)

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

Monday, April 3, 2017

March 2017 Summary

A wet March that was colder than February

Somebody better check the calendar because it seems that somebody switched the weather for February and March.  In fact for only the 5th time in the 100 years of records in the region, the average temperature was lower in March than it was in February (the last time this happened was in 1984).

The overall temperature was almost half a degree below average, but this is still within the average range.  However, this was the first time there was an overall temperature that was even a little below the average since April of last year.

It was a wet month with 90.2 mm of total precipitation compared to the average of 61.0 mm.  Interestingly, even with the cooler temperatures, a lot of that precipitation came down as rain instead of snow.  We only got 12 cm of snow compared to the average of 26.5 cm, this brings the total for the season up to 125 cm which is less than the 150 cm average for the end of March.

Summary for March 2017:
Maximum Temperature 17.1°C
Minimum Temperature -15.4°C
Average Daily High Temperature 2.7°C (Long term average 3.6°C)
Average Daily Low Temperature -5.6°C (Long term average -5.6°C)
Total Precipitation 90.2 mm (Long term average 61.0 mm)

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

Saturday, March 4, 2017

February 2017 Summary

The warmest February ever 

In what should not be a surprise to anyone, it was the warmest February that we have experienced in the 100+ years of records in the region.  The first half of the month saw temperatures that oscillated both above and below zero, but it was not until the 18th that the crazy heat came in.  The month ended with 12 days where the high temperature was over zero including some days that were over 15 degrees above the average.

Overall the temperature was 4.4 degrees above average which was almost half a degree more than the previous warmest February back in 1998.  The high of 15.1°C on the 23rd was the highest February temperature we have ever seen in the region, in second place was the 15.0°C which happened the day before.

The precipitation total was 68.0 mm, just enough to put it into the above average range.  Given the high temperatures, it is not surprising that we got about half the average amount of snow during the month (17.5 cm compared to 30.3 cm).  Even though the last 2 months have only seen half the average snowfall, the snowy December means that that the total snowfall of 113 cm is only a little less than the 125.6 cm we would expect at this point in the snowfall season.

Summary for February 2017:
Maximum Temperature 15.1°C
Minimum Temperature -15.3°C
Average Daily High Temperature 3.4°C (Long term average -1.2°C)
Average Daily Low Temperature -5.6°C (Long term average -9.7°C)
Total Precipitation 68.0 mm (Long term average 54.9 mm)

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

Friday, March 3, 2017

2017 Weather Station Contest is on!

The 2017 edition of the UW weather station contest is now on!

Can you guess for the first time the first time the weather station will record a temperature of 20C?

Find out all the details and enter the contest here:

Don't delay - you have to enter the contest by Wednesday, March 8th, 2017 at 2:00 pm.

Thursday, February 2, 2017

January 2017 Summary

A wet, warm, and “dreary” January

There were four cold days in the first part of the month, but that was about it for the really cold weather.  As well as a few days in the high single digits we also saw 12 days in a row above zero, which is something that we haven’t seen in January since 1944.  Put that all that together and it is not surprising that overall it was over 3 degrees above average, making it the warmest January since 2006.

With the 111.2 mm of precipitation in the month it was the second highest total in the last 18 years (2013 had a bit more with 114.7 mm), while most of it (81.4 mm) fell during the very wet first half of the month.  Of that precipitation there was only 20 cm of snow, less than half of the average of 43.7 cm.

Then we get to the “dreary” question.  The background is that at the UW weather station we measure the amount of incoming solar radiation, which is correlated to the number of hours of sunshine but not technically exactly the same thing.  Also keep in mind that this is the only source of this kind of data in the area, so records only go back to the start of the weather station in 1998, unlike precipitation and temperature which have records going back to 1915. 

So based on what we measure, the overall average of 47 Watts per square metre of incoming solar radiation was the lowest January value in the history of the station and much lower than the average of 81.7 W/m2.  Also I made an arbitrary and non-scientific criteria that if a day never had a reading of over 200 W/m2 then it was a “dreary” day.  Using this, the number of dreary days we had was 13 this January putting it well above the average of 7.5 and again the most we have seen in that past 19 years.

Summary for January 2017:
Maximum Temperature 8.2°C
Minimum Temperature -20.9°C
Average Daily High Temperature -0.1°C (Long term average -2.6°C)
Average Daily Low Temperature -6.4°C (Long term average -10.3°C)
Total Precipitation 111.2 mm (Long term average 65.2 mm)

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

Sunday, January 22, 2017

Longest January streak of above zero days in a while

As of January 22nd we have had 8 days in a row of days with above zero temperatures and the current forecast is for 4 more.  If we get to 12 days it will be longest streak of above zero days since we had 13 back in 1944 from Jan 19 to 31.

Note that this only counts days in January, for instance 2007 started with 8 days above zero, but this was after 23 to end off 2006, so the total streak there was 31 days, just not all in January.

Tuesday, January 10, 2017

2016 Summary

University of Waterloo Weather Station Annual Summary - 2016

Considering that April was the only colder than average month during the year, it is not that surprising that 2016 came in as one of the warmest we have seen in the 100 years of weather records in the region.  Overall the average temperature was 8.69ºC putting it behind only 2012 and 1998.

The year started off in the middle of the very warm winter of 2015-16 resulting in the first 3 months being all warmer than average, this included a high temperature of 14.2ºC on the third of February which was the highest February temperature we have seen in the region.

Things turned around in April with the only colder than average month of the year that was also the fourth coldest April in the region’s weather records.

The warm end of the Spring in May transitioned into the hottest summer we have had since 1955 and the third highest overall.  The 19 days above 30ºC during the summer contributed to the 27 we had in total for year, this is much more than the average of 8, but much less than the 49 we saw in 1955.

This then continued into the fall with September to November all coming in at over 2.5 degrees higher than average including: September being the warmest since 1959 and the fifth hottest overall and November the sixth warmest and the most days over 10ºC at 20.  But as we have seen a lot of warm Fall seasons lately, this Fall wasn’t that significant even these really warm temperatures.

As often happens there were wet and dry months during the year, for 2016 the year started with a few average months for precipitation.  Then March came in over twice as wet than average, but this quickly changed as for the most part it was a very dry summer.  It would have been historically dry if not for a 10 day period in August when almost 150 mm fell, this resulted in August being the 7th wettest all time.

For the rest of the year we saw pretty much average precipitation which helped in putting the final total within the average range.  The final total came in within the average range at 891.0 mm, which is a little below the average of 916.3 mm.

As for snowfall, we saw 100.5 cm of snow since the beginning of January, which is about average for that time of year.  But the 75.5 cm in the second half of the year (mostly from December which saw almost twice the average for the month) put the total for 2016 of 176.0 cm which is above the annual average of 159.7 cm.

So the final story of 2016 is the overall heat during the year and how dry it was during most of the summer.  But there wasn’t a whole lot in terms of extreme events, in fact in the list of extremes that are listed on the next page there was not one that was exceeding during this past year (of course this will get harder as more data is added to the record, but usually we have seen at least one or two extremes every year).

Summary for 2016:

Average Daily High Temperature: 14.10°C (average 12.05ºC)
Average Daily Low Temperature: 3.28°C  (average 1.94ºC)
Total Precipitation: 891.0 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 3, 2017

December 2016 Summary

A wet and snowy December with average temperature 

There was a much colder than average week in the middle of December that was offset by a warmer start and finish to the month, resulting in an overall temperature of 0.3 degrees above average.  This put the month within the average range for only the second time this year compared to 1 below average month and 9 above.

The precipitation was nicely within the average range for most of the month, but a few storms in the last week (including the rain on Boxing Day) resulted in the total finishing above average.  The total of 91.0 mm was well above the average of 71.2 mm.

With a total snowfall of 73 cm, it was the snowiest since 2008 (when we had 95.5 cm) and almost double the average of 37.2 cm.

Summary for December 2016:
Maximum Temperature 8.6°C
Minimum Temperature -14.9°C
Average Daily High Temperature -0.3°C (Long term average 0.2°C)
Average Daily Low Temperature -5.6°C (Long term average -6.8°C)

Total Precipitation 91.0 mm (Long term average 71.2 mm)

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