Alsask Lake is a closed basin lake in the Canadian province of Saskatchewan, about south-east of Alsask. The lake is a natural source for sodium sulfate and until 1991 an extraction plant was operated by Francanna Minerals (Sodium Sulfate Company).
Alsask experiences a semi-arid climate (Köppen climate classification: BSk). Winters are long, cold and dry, while summers are short and warm. Precipitation is low, with an annual average of , and is heavily concentrated in the warmer months.
The weather station is located adjacent to the lake. <div style=width:79%>
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Fish commonly found in Alsask Lake include northern pike.