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Okanogan Climate

Hot, dry summers and cold, snowy winters distinguish the Okanogan from its neighboring ecoregions.

In the west, the Okanogan Valley lies under the Cascade Mountains’ rain shadow. Annual precipitation measures less than 12 inches. On the ecoregion’s eastern edge, precipitation roughly doubles as storm fronts bump up against the rise of the Canadian Rocky Mountains.

In the summer, hot air flows northward from the Columbia Plateau, driving daily highs into the 90s and even the triple digits.

In the winter, cold, dense Arctic air can stream out of Canada. In 1968 this dropped temperatures to -48º F at Mazama and Winthrop, a record for Washington State.


For details of this ecoregion within Washington, click a subheading in the left column.

View the more general description of this ecoregion in North America

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