Climate Trends and Variations Bulletin
Winter Summary 2012/2013
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, first nationally, followed by the regional highlights.
The national average temperature for the winter of 2012/2013 was 1.6°C above baseline average (defined as the mean over 1961-1990 reference period), based on preliminary data, which is the 18th warmest observed since nationwide records began in 1948. The warmest winter on record was 2009/2010 when the national average temperature was 4.1°C above the baseline average. The coolest winter on record was 1971/1972 when the national average temperature was 3.5°C below the baseline average. As the temperature departures map below shows, temperatures across most of the country were at or above the baseline average this winter. Northern Quebec and Labrador experienced winter temperatures more than 4°C above the baseline average. A small portion of the northern Yukon and western Northwest Territories was the only area that was cooler than the baseline average in the winter of 2012/2013.
Temperature Departures from the 1961-1990 average - Winter (Dec, Jan, Feb) 2012/2013
The time series graph below shows that national average winter temperatures have remained at or above the baseline average since 1996/1997. The red dashed linear trend line indicates that, when averaged across the nation, winter temperatures have warmed by 3.2°C over the last 66 years.
Winter National Temperature departures and long-term trend, 1948 - 2013
The average winter temperature for 2012/2013 was amongst the ten warmest on record in only one climate region: Great Lakes/St. Lawrence (ranked as 8th warmest, at 2.5°C above the baseline average). The coolest region, relatively, was the Mackenzie District, which was still warmer than the baseline average (35th warmest, 0.7°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 winter temperature trends over the 66 years of record. The strongest increase in winter temperatures is observed in the North B.C. Mountains/Yukon region with an increase of 5.4oC over the period of record (1948-2013). The weakest temperature trend is observed in the Atlantic Canada region (0.7°C over the same period).
As a whole, Canada experienced its third driest winter in 2012/2013 (17% drier than the 1961-1990 average). Over the period of record, the wettest winter was 1996/1997 (18% above the baseline average) and the driest was 1956/1957 (20% below the baseline average). The precipitation percent departure map for the winter of 2012/2013 (below) shows that most of the western half of the country was really dry, with the exception of central Alberta, which was the only area of exceptionally high precipitation this winter. Eastern Canada, for the most part, had precipitation levels near the baseline average.
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 - Winter (Dec, Jan, Feb) 2012/2013
The national precipitation percent departures graph below shows that the last three winters have been drier than the baseline average.
Winter National Precipitation Departures with Weighted Running Mean, 1948 - 2013
The Mackenzie District had its driest winter on record, 37% drier than the baseline average. The winter of 2012/2013 ranked among the ten driest winters in three other regions: North B.C. Mountains/Yukon (2nd driest, 40% below the baseline average); South B.C. Mountains (4th driest, 33% below the baseline average); and the Pacific Coast (5th driest, 28% below the baseline average). No region was wet enough to rank among the ten wettest winters and only one region experienced a wetter than the baseline average winter. Winter precipitation in the Great Lakes/St. Lawrence region was 11% wetter than the baseline average, which ranked as the 16th wettest winter. 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 winter’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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