Washington has a wide range of climates because of its mountains, ocean influence, and internal elevation differences. Most of western Washington has a **marine west coast climate** (Köppen **Cfb**), with mild temperatures, wet winters, and relatively dry summers. Parts of the Olympic coast are among the wettest places in the contiguous United States. Eastern Washington is drier and more continental, with large areas classed as **semi-arid** (**BSk**) and some warmer-summer Mediterranean or dry-summer continental variations in valleys and uplands.
A simple statewide summary can be misleading because Seattle, Spokane, Yakima, and the Olympic Peninsula experience very different weather. Western lowlands often have cool, damp winters and pleasantly mild summers. Eastern Washington typically has hotter summers, colder winters, lower humidity, and much less annual precipitation.
| Climate Feature | General Pattern | |---|---| | Average winter temperatures | Often near the 30s–40s °F in western lowlands; colder in eastern and higher-elevation areas | | Average summer temperatures | Often 70s °F in many western cities; warmer to hot in eastern valleys and basins | | Rainfall | Very high on the Olympic coast and western slopes; much lower east of the Cascades | | Snowfall | Common in mountains; variable in lowlands; more frequent in parts of eastern Washington | | Humidity | Higher west of the Cascades; lower in much of the interior | | Best time to visit | Often late spring through early fall for general travel; winter for mountain snow sports |
Washington is vulnerable to several natural hazards:
- **Volcanic hazards** from Cascade volcanoes, especially Mount Rainier, Mount St. Helens, and others - **Earthquakes** from regional fault systems and the Cascadia Subduction Zone - **Flooding** in river valleys and coastal areas - **Wildfire and smoke** especially in eastern Washington and increasingly in some western areas during dry summers - **Landslides** in steep, wet terrain
_Data not readily available for this location._