Rainfall in Washington varies dramatically going from east to west. The Olympic Peninsula's western side receives as much as of precipitation annually, making it the wettest area of the 48 conterminous states and a temperate rainforest. Weeks may pass without a clear day. The western slopes of the Cascade Range receive some of the heaviest annual snowfall (in some places more than water equivalent) in the country. In the rain shadow area east of the Cascades, the annual precipitation is only . Precipitation then increases again eastward toward the Rocky Mountains.