October Review / November Preview

October 2017 certainly went out a wintery note, but today we'll take a look back over the whole month.

High Temperatures

October started pretty warm, but then things cooled off for a week. Then the last half of the month was pretty warm again, with 2 recent records on the 17th and 28th, both just below 20°C. The final few days of the month felt cold, but that was actually pretty close to the average.

Looking at the numbers in more detail, this October was pretty typical. We had one day with a high above 20°C, two weeks above 10°C, and no highs below 0°C. 

Thinking back to last year, 2016 was one of those cold Octobers that we get every few years - along with 2012, 2009, 2006, etc.

Low Temperatures

The path of the Low temperatures is similar to what we saw with the highs - the same coldsnap earlier in the month, and then warm nights later on.

It is a little surprising to think that we actually had 18 Lows below freezing last month, including 2 below -5°C. That isn't unusual, but it is on the cool side of things. Some Octobers like 2013 and 2014 only had 8 night below 0°C.

Warm & Cold Months

So how does October compare overall?

We looked at this chart a few weeks ago, and it compares the average temperature of the whole month to the average from the 20th century. This is a combination of all the daily High and Low temperatures, and October 2017 was just a bit above the 20th century average. It was also quite close to the 5-year average, although that recent average is dragged-down by the cold October 2016.

November Temperatures

As we head into November things are going to cool off. Last November was very warm, with a mini-heatwave to start the month. In a warm year - like 2016, 2009, 2008, 2005 - half of the month might break above 5°C. But in a cold November - like 2013, 2012, 2006 - we might only get 2 or 3.



From 2010-2015 we had a string of Novembers with coldsnaps, with Lows dropping into the range of -18°C all the way down to -30°C in 2014. We didn't get anything like that in November 2016, and that was also a lot more rare prior to 2010. Hopefully those will go back to a once-every-5-years frequency, rather than once-every-year.

Precipitation

In terms of precipitation, with 25mm recorded at the International Airport we were right around the average. Blatchford recorded a little bit less again, at 18mm.

Snow

The International recorded 15cm of snow in October, which was above average, but below what we got in 2016. 5cm of that snow was from the Halloween snowstorm, and the rest was from earlier in the month including 9.2cm on October 1st & 2nd.

Blatchford doesn't record snowfall, but I know that it didn't have a big snowstorm at the beginning of October. When dealing with precipitation or snow I always have to give the caveat that I use the International because its historical data is better than Blatchford's, but unfortunately the International isn't necessarily representative of Blatchford. That's the case here, where the city probably got a total of about 5cm of snow right at the end of the month, compared to the 15cm at the airport.