About this Bulletin

Bulletin for Canada (CTVB) places the most recent season and year in historical context by utilizing timely data sets from synoptic weather reporting stations in Canada and historical data contained in the Historical Canadian Climate Database (HCCD). Other analyses based on HCCD data sets have been published in State of the Environment Reports Nos. 92-2 and 95-1, in Trends ‘93 and elsewhere. The current data sets, for the most recent season or year, are preliminary and should be used with caution. Results of these analyses, including regional departures, trends and rankings are subject to change as final data sets are received, processed and retained in Canada’s national climate archives. CTVB is a new forum for presenting national and regional climate analyses (temperature and precipitation only at this time) for Canada and as such it will continue to be under development with content and format changes likely from time to time as new research initiatives and results become available.

Average temperatures and total precipitation are analyzed with respect to eleven broad climatic-geographic regions. National and regional time series are constructed of seasonal and annual departures from the 1951-1980 reference period averages, in Celsius degrees for temperature, and as percentage departures for precipitation. The HCCD contains historical data sets for 131 Canadian locations which are combined with current data at the end of each season and year. These current data sets are preliminary and may contain values that were estimated to fill missing data gaps. As well, some preliminary quality control has also been performed on these to minimize the effect of spurious data.

For both temperature and precipitation, national and regional analyses are carried out for the 1948-present common period for all regions. For temperature linear trend analysis is applied, and for precipitation a weighted running mean (nine-point binomial filter) is used. These serve as indicators of long-term change with respect to time. Each departures series is sorted and arranged in sequence, from warmest to coolest for temperature, and from wettest to driest for precipitation, with the most recent departure-year ranked against all others in that series. In the most recent version of the HCCD, 1948 marks the earliest year of the period over which reliable inter-regional comparisons are feasible.

The national analyses also include consecutive seasons departures series, for both temperature and precipitation, for each year since 1985.

Queries or comments should be directed to:

Environment Canada
Meteorological Service of Canada
Climate and Atmospheric Research Directorate
4905 Dufferin Street
Downsview, ON M3H 5T4
Attn: Climate Monitoring and Data Interpretation Division

CTVB Author and Web Administrator: Bob Whitewood

CTVB Climatic Data Supplier : T. Jang

French translation : D. Pokorn

Please identify Environment Canada as the source when using material originating in this bulletin.

Meteorological Service of Canada - Environment Canada - Government of Canada

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