Washington has two distinct climate zones. Mild, humid, summer days west of the Cascades rarely rise above 26°C (79°F), and winter days seldom drop below 8°C (46°F) while the east of the state has warm summers and cool winters. Western Washington experiences frequent cloud cover, fog and drizzle, and the western slopes of the Cascades receive up to 508cm (200 inches) annual snowfall. In the rain shadow east of the Cascades, the annual precipitation is only 15cm (6 inches).

Warm winter clothes are needed in the coldest months. Light-to-medium weights are advised for the summer. An umbrella can come in handy any time of year.