Tri-Cities, Washington - Climate and Geography

Climate and Geography

The Tri-Cities are in a semi-arid climate, receiving an average of 5 to 7 inches (130 to 180 mm) of precipitation every year. Winds periodically exceed 30 mph (48 km/h) when Chinook wind conditions exist. While there are an average 300 clear days every year, these are mainly between April 1 and November 1. Temperatures range from as low as 0 °F (−18 °C) in the winter to as high as 110 °F (43 °C) in the summer, and even reached 115 °F (46 °C) in July 2006. The region receives occasional snow most years but has received as much as 20 inches. Due to the semi-arid climate and subsequent large amounts of sand, a perpetual annoyance to residents is the amount of dust blown about by the frequent winds. Thanks to the aforementioned rivers, a large amount of cheap irrigation is available.

Washington is the most northwest of the lower 48 states—consequently, the area is in the Pacific Standard Time Zone. The Tri-Cities makes up the largest metropolitan area in the southeastern quadrant of Washington. The large Cascade Mountain Range to the west contributes to the semi-arid climate, which is far drier than the famously wet western side of the state. See rain shadow for more information on this phenomenon. The region's climate results in a shrub-steppe ecosystem which has 18 endemic plant species. Just west of Richland, the Fitzner/Eberhardt Arid Lands Ecology Reserve was established to study the unique plants and animals found in the local shrub steppe ecosystem. It is the largest tract of shrub-steppe ecosystem remaining in the U.S. state of Washington.