Source of Climate Data
All climatological charts were developed from data collected, quality controlled and archived by Environment Canada. The National Climate archive resides at the Canadian Meteorological Centre in Montreal, Quebec.
Types of Stations
Most climate data is collected either at climate stations, or at major stations operated by federal and provincial organizations. Climate stations are operated by volunteers who record temperature extremes and precipitation data twice per day. Most of the major stations record a larger suite of weather conditions including wind speed and direction, pressure, humidity, cloud information, visibility, various precipitation characteristics, obstructions to vision, etc.
Length of Station Data Records
The earliest weather reporting done in Saskatchewan dates from the 1880's. Thus our longest data records are around 120 years. Since only a few Saskatchewan stations have climate records dating back before 1900, we have chosen to limit our analysis to the 1900 - 2000 period. Notwithstanding this decision, many climate stations have less than 100 years of record. In selecting a dozen or so representative stations for the province, some stations have the full 100 years of data while others have shorter data records.
Sample Data Set
Environment Canada has made available a sample set of monthly climatological data. This sample data is identical in format to that used in creating the charts displayed for the Saskatchewan sites. Students, and others, may wish to utilize this data to perform data manipulation, statistical calculations and testing, charting, etc.
Season Definitions
The annual charts are based on data for a 12 month calendar year. The seasons are defined as follows: winter being December (previous), January and February; spring being March, April and May; summer being June, July and August; and fall being September, October and November.
Temperature Measurement
Temperatures are measured using either a thermometer or by electronic thermocouples.
Mean Temperature Calculation
Daily mean temperatures are determined by performing a simple arithmetic average of the daily maximum and minimum temperatures. Monthly and annual mean temperatures are computed from the daily mean temperature values.
Rainfall Measurement
At the present time, all Canadian weather observers use the Meteorological Service of Canada (MSC) Type-B rain gauge. This plastic gauge replaced the older standard (copper) gauge in the 1970's. The Type-B gauge is graduated at 0.2 mm increments. Precipitation measurements are taken every six (6) hours at the main reporting stations and twice daily at the climate stations.
Snowfall Measurement
The unmelted snow depth is measured using a ruler.
Snow Water Equivalent
At climate stations, the observer uses a 10:1 ratio between the snowfall and the water equivalent of the freshly fallen snow, i.e. a one centimetre snowfall is recorded as one millimetre (mm) of liquid precipitation. At the larger stations, the six-hourly snowfall is captured in a Nipher snow gauge. The snow is then melted and the actual water content of the snowfall is counted as snow water equivalent (SWE). Nipher snowgauges were introduced in the 1960's. Prior to this, all stations used the 10:1 ratio. Automatic weather reporting stations use weighing gauges to determine the SWE.
Trend Lines
The trend lines shown in red on the charts are the 'best fit' linear trend based on the data plotted. Some caution should be used in interpreting trend lines for stations with shorter data records. A shorter data record may not be as representative of the fuller range of expected climate conditions.
