CBC pronounced 2010 Canada’s warmest year on record. I pretty much live outside all the time and have a pretty good sense of the weather. For me 2010 will be remembered as the year without a summer. So I thought I would dig deeper than a single average covering such a large landmass.
I data mined the monthly means for a representative cross section of Canada. In the chart, I have color-coded the monthly anomalies as calculated by the delta between the monthly mean and the monthly averages from Environment Canada from their 1971-2000 dataset. The results show what is hidden in an average.
Also included is a scaled 2010 monthly sea surface temperature graph to highlight its effect on Western Canada.
2010 Monthly Temps in 8 Canadian Regions
I note the following observations.
1. Canadian weather is regional. It is a product of regional dynamics.
2. Warm anomalies occurred in the coldest months.
3. Cold anomalies occurred in the warmest months and coincide with the switch between warm Pacific water and cold Pacific water as shown in the graph.
4. Based on 1&2, temperature extremes were decreased. 2010 Canadian weather data was primarily presented as being extreme yet temperature range was actually decreased.
5. There appears to be a lag of a couple months between the peak el Niño in January and the March anomalies. There also appears to be a “pulse” of La Niña making its way from west to east.
A yearly national temperature average conveys no practical information. The claim of hottest year ever bears little resemblence to the data above even if it may be mathematically correct (UHI effects and other data corruption notwithstanding.)
Method and Sources
I chose weather stations that represented a cross section of Canadian cities in all the regions. Since 99% of Canada’s population lives near these stations, they seemed most relevant though clearly they represent populated Canada not geographic Canada. I first went to Environment Canada’s archive but found it to be swiss cheesed with missing data for many of my stations (hence the inclusion of little known Geraldton ON which is my proxy for Thunder Bay.) Above is Environment Canada’s less than usefull database.
To solve this problem, I used the database from weatherunderground which downloads and archives the daily weather data from these same stations that Environment Canada uses, primarily airports. They can be cross checked by their station ID number to ensure that means are compared to the correct data set.
Map showing locations of station data.