Ellensburg has a high-desert climate — cold dry winters and hot dry summers. June through September is the obvious window: long days, blue skies, and the river ranches at their greenest. July and August can push past 35°C, but evenings cool quickly.
The single weekend not to miss is Labor Day in early September, when the Ellensburg Rodeo, the Kittitas County Fair, and a vast street fair fill the town. Winter has its own attractions — the ski areas at Mission Ridge and the Cascades are an hour or two away — but Snoqualmie Pass can close without warning. Spring brings the migration of geese and swans through the Kittitas Valley wetlands.