 Omak experiences four distinct seasons. Summers are hot and relatively dry, with a daily average of 72.2°F (22.3°C) in July, while winter is the wettest season of the year, with 22.3 inches (570 mm) of snowfall between November and February. Spring and autumn are mild seasons with little precipitation. The city is located in plant hardiness zone 6a, according to the United States Department of Agriculture (USDA). In July 2012, a severe thunderstorm occurred in Omak, producing heavy rainfall, gusty winds and hail, and forced the temporary closure of U.S. Route 97 and requiring repairs to public streets. Omak was affected by the 1872 North Cascades earthquake — the state's largest historical earthquake — which occurred on December 14, 1872. The epicenter was at Omak Lake. The earthquake had a magnitude of between 6.5 and 7.0 and was followed by an aftershock. Another earthquake with minor shaking affected the city in November 2011.
