Climate Trends and Variations Bulletin - Annual 2012
This bulletin summarizes recent climate data and presents it in a historical context. It first examines the national temperature, and then highlights interesting regional temperature information. Precipitation is examined in the same manner.
The national average temperature for the year 2012 was 1.9°C above baseline average (defined as the mean over 1961-1990 reference period), based on preliminary data, which is the 5th warmest observed since nationwide records began in 1948. The warmest year on record was 2010 when the national average temperature was 3.0°C above the baseline average. The coolest year on record was 1972 when the national average temperature was 1.9°C below the baseline average. As the temperature departures map below shows, all of the country had temperatures at or above the baseline average this year, with most of the Northwestern Territories, Nunavut, Ontario, Quebec and Newfoundland experiencing temperatures more than 2°C above the baseline average.
Temperature Departures from the 1961-1990 average - Annual (Jan-Dec) 2012
The time series graph below shows that national average annual temperatures have remained at or above the baseline average since 1993. The red dashed linear trend line indicates that, when average across the nation, annual temperatures have warmed by 1.7°C over the last 65 years.
Annual National Temperature departures and long-term trend, 1948 - 2012
The average annual temperature for 2012 was amongst the ten warmest on record in eight of the 11 climate regions. The eight regions include: Great Lakes/St. Lawrence (ranked as 2nd warmest, but it is a virtual tie for 1st with 1998, at 2.3°C above the baseline average); Northeastern Forest (3rd warmest, 2.2°C above the baseline average); Arctic Mountains and Fiords (3rd warmest, 2.2°C above the baseline average); Arctic Tundra (4th warmest, 2.3°C above the baseline average); Atlantic Canada (4th warmest; 1.9°C above the baseline average); Prairies (7th warmest, 1.5°C above the baseline average); Mackenzie District (8th warmest, 2.0°C above the baseline average); and the Northwestern Forest (9th warmest, 1.4°C above the baseline average). The lowest ranked region, North British Columbia/Yukon, was still warmer than the baseline average (29th warmest, 0.6°C above the baseline average). A table listing the regional and national temperature departures and rankings from 1948 and a table that summarizes regional and national trends and extremes are available on request to CTVB@ec.gc.ca.
The trends, extremes and current year rankings table shows that all eleven climate regions exhibit positive annual temperature trends over the 65 years of record. The strongest increases in annual temperatures are observed in the Mackenzie District with an increase of 2.6oC over the period of record (1948-2012). The weakest temperature trend is observed in the Atlantic Canada region (0.8°C over the same period).
As a whole, Canada experienced near the 1961-1990 baseline average precipitation in 2012. It was the 33rd wettest year in the 65 years of record with national precipitation 1% above the baseline average. Over the period of record, the wettest year was 2005 (15% above the baseline average) and the driest was 1956 (12% below the baseline average). The precipitation percent departure map for 2012 (below) shows that most of the country received annual precipitations amounts close to the baseline average. Areas of southern B.C., Saskatchewan, and Manitoba, along with northern Quebec and eastern Nunavut had wetter than the baseline average conditions this past year. Northern Northwest Territories, western Nunavut, central B.C., south-central Alberta, southern Ontario, and Newfoundland and Labrador experienced drier than the baseline average conditions in 2012.
It should be noted that the baseline precipitation in northern Canada is generally much less than it is in southern Canada, and hence a percent departure in the north represents much less difference in actual precipitation than the same percentage in the south. The national precipitation rankings are therefore often skewed by the northern departures and do not represent rankings for the volume of water falling on the country.
Precipitation Departures from the 1961-1990 average - Annual (Jan-Dec) 2012
The national precipitation percent departures graph below shows that annual precipitation amounts have tended to be above the baseline average for Canada since 1971.
Annual National Precipitation Departures with Weighted Running Mean, 1948 - 2012
Of the eleven climate regions only one, the Northwestern Forest, experienced one of its ten wettest years on record in 2012 (10th wettest, 6% more precipitation than the baseline average). Also, 2012 ranked among the ten driest years on record in only one region, the Great Lakes/St. Lawrence region (ranked 3rd driest, 13% below the baseline average). Interestingly, this was the first year in the last decade that the Great Lakes/St. Lawrence region experienced drier condition than the baseline average. A table listing the regional and national precipitation departures and rankings from 1948 and a table that summarizes regional and national extremes are available on request to CTVB@ec.gc.ca.
This past year’s precipitation rankings for each region, along with the record wettest and driest years, are summarized in the extremes and current year rankings table.
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