Alberta's temperatures vary significantly throughout the year, with average winter temperatures ranging from around -7°C in the south to -18°C in the north. Typically, the months of November to March see daily average temperatures that are below 0°C. Average summer temperatures tend to be more consistent throughout the province, generally ranging between +16°C and +18°C. Plots from Fort McMurray and Lethbridge show the daily average temperatures throughout the year, illustrating some of the differences within the Province.

Because these numbers represent the average daily temperatures, the actual range between the observed maximum and minimum temperatures is even greater. At Fort McMurray, the maximum air temperature that has been recorded is +37°C, while the minimum is -51°C. For Lethbridge, the corresponding extreme values are +39°C and -43°C.

Alberta Environment provides a Provincial Air Temperature Summary for the most recent provincial air temperature information. For weather forecasts, Environment Canada's Weather Office provides both current and forecasted conditions.

Precipitation falls to the ground as both rain and snow. Average annual precipitation is highly variable across the province, with the Rocky Mountains and Foothills areas receiving the largest annual amounts. The driest part of the province is in the southeast corner; however, precipitation is also relatively low in the far north. Annual precipitation amounts well in excess of 1,000 to 1,500 millimetres (mm) are recorded higher in the mountains, while the southeastern portion of the province receives between 300 to 350 mm annually. Much of Alberta receives approximately between 400 to 550 mm of precipitation a year on average. However, precipitation amounts also vary significantly from year to year as shown in the accompanying table. For example, Edmonton receives about 460 mm on average, but the highest amount on record for one year is 745 mm and the lowest is 210 mm. In general, precipitation decreases as you move east away from the mountains and foothills and also as you move north. The Swan Hills, an extension of the foothills, are a notable topographic feature that increases precipitation in the north-central part of the province.

View a map of the long-term mean annual precipitation for the province, and the historical annual precipitation amounts for Edmonton and Calgary below.

Edmonton Annual Precipitation

Calgary Annual Precipitation

In general, about 25 to 35 percent (or one-quarter to one-third) of annual precipitation falls as snow, depending on where you are in the plains area of the province. Examples from Fort McMurray (where it is about one-third as snow) and from Lethbridge (where it is about one-quarter) are shown in the figures below. This proportion varies not only by location but also from year to year, ranging anywhere from 13 to 63 percent in a given year for these two examples.

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Fort McMurray Annual Precipitation

Lethbridge Annual Precipitation

For recent (daily/weekly/monthly) and seasonal precipitation amounts, take a look at Alberta Environment's Precipitation Maps. For weather forecasts, Environment Canada's Weather Office provides both current and forecasted conditions.

Evaporation in our environment is broadly divided into two main categories: evaporation and evapotranspiration. Evaporation, or lake evaporation, is the water that evaporates from water bodies such as lakes and ponds due to solar radiation, mild to hot temperatures, and wind. Evapotranspiration is the combination of evaporation from the soil and the transpiration that occurs from trees and plants. Evaporation losses are relatively high in Alberta, generally exceeding the average annual precipitation. Lake evaporation is highly dependent on solar radiation input; therefore it tends to decreases as you move north. The highest average annual values are around 780 mm for the region south of Calgary, while around Edmonton and in the central band of the province the average annual values are in the 650 mm range. Further north, around Fort McMurray and High Level, the values drop off to around 575 mm. Note that these numbers reflect values for lakes and other relatively large water bodies; for smaller, shallower water bodies the annual evaporation would be higher.

As expected, most of the annual evaporation occurs in the summer. Evaporation typically peaks during July, but about 75 percent of the annual total occurs in the four months from May to August. This increases to over 90 percent between April and September. As an illustration of the seasonal pattern, average monthly evaporation at Edmonton is shown in the chart on the right, and works out to an average annual evaporation of around 665 mm. Like precipitation, evaporation totals will vary from year to year in response to climatic factors.

Unlike precipitation, evaporation from a lake cannot be measured directly and therefore must be estimated using energy balance calculations. It can be calculated using a variety of formulas that include temperature, wind, solar radiation, sunshine duration, relative humidity and so on.

View a map of the long-term mean annual precipitation for the province.

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