Climate Trends and Variations Bulletin for Canada

For the third consecutive season, autumn 1998 in Canada was the warmest on record. The national average temperature for the three months (September, October, November), based on preliminary data, was 2.3°C above normal. The autumn national temperature departures table shows 1948 was the second warmest autumn, at 1.7°C above normal, out of the 51 years since comparable nationwide temperatures records began in 1948. The coolest autumn was 1986 at 1.8 below normal. Statistically, in an unchanging climate, Canada could expect an autumn anomaly like this autumn’s about every 170 years. Most of Canada experienced temperatures more than one degree above normal. The Arctic islands felt temperatures more than 5°C above the long term average. Only southern Yukon, Northern British Columbia, central Alberta and most of the Maritimes experienced normal or slightly below normal temperatures this autumn. Even with this record warmth, the linear trend for autumns is still slightly negative, -0.2°C over the 51-year period. Nationally, over the last 20 years the number of autumns above normal and below normal is even. The consecutive seasons graph shows this autumn extends the above-normal streak to six seasons.

The Autumn of 1998 was a balance between much above normal and much below normal precipitation. The net result was an autumn that was 17th driest at 1.5% below normal. The autumn national precipitation departures table shows that the driest autumn nationally was in 1976 (-20.3%) and the wettest was in 1981 (+24.1%). The accompanying map shows the wetter than normal areas are southern British Columbia, central Alberta, southern Saskatchewan, and some of the Maritimes. The rest of the country is either above or near normal. It should be noted that "normal" 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. In the last ten years only this autumn and the autumn of 1993 were below normal. The only other autumn in the last 20 years with a below normal value was 1987. The consecutive seasons graph shows that the four seasons in 1998 have been below average.

11-month summary

What a year it has been so far! Canada has had it's warmest year since nationwide measurements began in 1948 with the temperature 2.4°C above normal. The next warmest year, 1981, was half a degree cooler. These facts, along with global above normal temperature records for 1998 through November, are further evidence that we are living in a warmer climate. Statistically, in an unchanging climate, a year like this year could be expected only once every 1250 years. The map below shows that most of the country has experienced temperatures at least 2°C above normal. The graph below shows just how outstanding 1998 has been, as well as the linear trend for this period over the 51-year record at +0.8°C.

Over the past year, 6 months have set new warmest temperature records (February, April, May, July, August, September) and two months (June, and November) were second warmest. All 11 months have been warmer than normal.

1998 has been a dry year, so far. Canada has had it's 9th driest year for the first 11 months, at 3.3% below normal. The map below shows the drier than normal area extends from the Yukon south and east, covering most of British Columbia, most of Alberta, the northern half of Saskatchewan, through the middle of Manitoba, covering most of Ontario and continuing into the western edge of Quebec. Only the Northwest Territories, along the 49th Parallel and the Maritimes have seen above normal precipitation so far this year. The graph below shows in the last twenty years, there have only been 2 years with below normal precipitation.

	Last modified : December 4,1998 URL of this page : http://www.tor.ec.gc.ca/ccrm/bulletin/index.html Copyright © 1998. All rights reserved
You are on the Green Lane™, Environment Canada's World Wide Web Site

Climate Trends and Variations Bulletin for Canada

Autumn 1998 Temperature and Precipitation in Historical Perspective

National Overview

11-month summary