Monthly weather forecast and climate
Washington, USA

Flag of Washington, USA
Flag of Washington, USA

The climate of Washington

Washington mainly exhibits continental climate (Köppen climate classification Csb, Cfb, Dfb) in the west and semi-arid type in the east (Köppen BS, BW) of the Cascade Range. Idaho in the east, Oregon in the south, the Pacific Ocean to the west, and the Canadian province of British Columbia in the north, border the state. The climate varies substantially from west to east, spanning from oceanic, Mediterranean, and subarctic to semi-arid. The Pacific Ocean, the Olympic, and Cascade mountains chiefly influence the climate of the state.

Washington, the Evergreen State, lies at the extreme northwest of the United States, with an average elevation of 520 meters above seas level. The Cascade Range that runs north-south bisects the state into a wet western part and a dry eastern part. The topography consists of high mountains, volcanoes, dense forests, temperate rainforests, rivers, semi-arid steppe, and deserts. The rain shadow region of the Cascade Mountains receives scanty rainfall of 6" (152mm), while the windward side sees abundant snowfall that reaches 200" (5080mm) annually. The temperate rainforests lie on the western side of the Olympic Peninsula, where the annual rainfall crosses a massive 160" (4064mm).

Summers in western Washington are fresh and relatively dry, while they are warmer in the east. The average high temperatures peak at 78°F (25.6°C) in July, while day temperatures reach 105°F (40.6°C) to 115°F (46.1°C) in many places in the east. Winters are mild and wet, with mainly cloudy skies, and long-lasting drizzly rain. The average low temperatures drop to 23°F (-5°C) in January, while night temperatures regularly dip between -10°F (-23.3°C) to -20°F (-28.9°C). Wind speeds reach 40 to 50mph (80.5km/h) during the cold months. Chinook winds that rapidly raise temperatures occasionally blow during the winter. Thunderstorms occur for four to eight days in the lowlands and seven to fifteen days in the mountains. A few hailstorms cause damage to crops during the winter.

The average annual precipitation is an ample 42" (1067mm) in Washington. The precipitation varies from 20" (508mm) in the rain shadow of the Olympus mountains region to 150" (3810mm) on the windward side of the mountains. Rainfall is light to moderate but lasts for long periods. The annual rainfall varies from 7" (178mm) to 9" (229mm) at the confluence of the Snake and Columbia Rivers, to 15" (381mm) to 30" (762mm) along the eastern border. Fog can last up to noon during late summer and early fall in the lowlands, while higher elevations are sunny. Snowfall varies from 10" (254mm) in the Puget Sound area to 75" (1905mm) in eastern Washington. Snow remains on the ground until June at higher elevations, while mountain peaks above 2500 meters remain snow-capped throughout the summer. Mount Rainer and Mount Baker record some of the most significant snowfall and snow depths in the United States. Washington records 126 to 200 sunny days annually.

The highest temperature on record in Washington is 118°F (47.8°C) at Ice Harbor Dam on August 5, 1961, while Winthrop and Mazama recorded the lowest temperature of -48°F (-44.4°C) on December 30, 1965.

The best time to visit Washington

The best time to visit Washington is from June to September during summer and early fall seasons. The skies are clear, the days are sunny, and the conditions are pleasant. The temperatures range from warm to moderately hot across the state. Camping, fishing, and hiking in the higher mountain lakes and streams region begins after the melting of snow in late spring and lasts until fall. The exciting whale watching season lasts from April to October. Summer is the peak tourist season, but May and September have pleasant weather and fewer crowds.

The worst time to visit Washington

The worst time to visit Washington is from December to February in the cold season. Winters are severely cold in the majority of the state. The skies are gray, the conditions are chilly, and the atmosphere is wet. Moist air from the ocean and the formation of the low-pressure center during fall and winter starts the wet season by the beginning of October. Rainfall is heavy in the high and windward side of the mountains. Snowfall is massive in the highlands and ample in the rest of the state except for the coastal regions. Strong winds with speeds of 50mph (80.5km/h) add to the chill factor. Winter sports attract many tourists to mountain resorts with activities like skiing, snowboarding, and snowshoeing.

Weather hazards

Washington lies in the Pacific Ring of Fire and the Cascade Volcanic Arc, which is susceptible to frequent volcanic and seismic disturbances. Mount Rainier has a history of large, destructive eruptions, while Mount St. Helens last erupted in 1980. Additionally, Washington is prone to wildfires, thunderstorms, floods, and snowstorms in late spring, summer, and winter. The melting of snow causes flooding in low-lying areas during late spring. Snowstorms are frequent in the winter and blizzards deposit massive amounts of snow in the upper mountain ranges.

Weather in January

January is usually the coldest month of the year in Washington as the temperatures drop alarmingly. The bottom may hit -25°F (-31.7°C) or lower in many areas such as Leavenworth and Winthrop. The average low temperatures are in the frigid 18°F (-7.8°C) to 28°F (-2.2°C), while the average high temperatures are in the cold 30°F (-1.1°C) to 40°F (4.4°C) zone, with mild temperatures in the coastal regions. The coastal belt and mountain slopes are rainy with 12" (305mm) to 15" (381mm) of rainfall, which makes the conditions challenging, especially with heavy snow at high altitudes. Weather in January »

Weather in February

February is cold in Washington with gray skies, chilly winds, and plenty of snow. The average low temperatures are in the freezing 21°F (-6.1°C) to 31°F (-0.6°C) zone, while the average high temperatures are in the mild 36°F (2.2°C) to 46°F (7.8°C) zone across the state. Weather in February »

Weather in March

March is cold in Washington during the early days of the beautiful spring season. Day temperatures rise a little to register in the average 43°F (6.1°C) to 53°F (11.7°C) range, while the average night temperatures remain in the cold 25°F (-3.9°C) to 35°F (1.7°C) range. Weather in March »

Weather in April

April steadily increases the temperatures in Washington with the advance of the spring season. Snow disappears on the ground by the end of the month except for the upper mountain ranges. The precipitation ceases considerably and registers an average of 2.9" (74mm) in the state. The average high temperatures are between a warm 50°F (10°C) to 60°F (15.6°C), while the average low temperatures drop to the cold 30°F (-1.1°C) to 40°F (4.4°C) zone. Weather in April »

Weather in May

May is a wonderful spring month in Washington with warm weather. The average high temperatures are in the pleasant 58°F (14.4°C) to 68°F (20°C) zone, while the nights are mild in the average range of 35°F (1.7°C) to 45°F (7.2°C). Weather in May »

Weather in June

June begins the warm summer season in Washington with moderate sunshine and dry conditions. The average high temperatures are in the wonderful 65°F (18.3°C) to 75°F (23.9°C) range, while average low temperatures are in the comfortable 40°F (4.4°C) to 50°F (10°C) zone. Weather in June »

Weather in July

July is the hottest and driest month of the year in Washington with the average high temperatures in the range of 73°F (22.8°C) to 83°F (28.3°C) and the average low temperatures in the 45°F (7.2°C) to 55°F (12.8°C) zone. Weather in July »

Weather in August

August is a warm summer month in Washington with beautiful weather and light rain. The Pacific coast swarms with visitors from all over the state and the country to enjoy the warm waters. Temperatures average between 50°F (10°C) to 73°F (22.8°C) but vary considerably by altitude and region. Weather in August »

Weather in September

September brings the colorful autumn season to Washington with warm temperatures amid a slight uptick in rainfall. The Pacific Coast sees 2" (51mm) to 4" (102mm) of rain, while the average precipitation in the state is a moderate 2" (51mm). The average high temperatures are in the ideal 65°F (18.3°C) to 75°F (23.9°C) range, while the nights are relatively cooler in the average low-temperature range of 40°F (4.4°C) to 50°F (10°C). Weather in September »

Weather in October

October is the time of peak fall foliage in Washington as the wet season beings in the state. Aspens, maples, larches, and many other trees display brilliant shades of red, orange, yellow, gold, and purple. Washington is one of the best places in the United States for fall visits, with its broad palette of colors in the backdrop of panoramic mountains. The average high temperatures are in the warm range of 52°F (11.1°C) to 62°F (16.7°C), while average low temperatures register in the cold 32°F (0°C) to 42°F (5.6°C). Weather in October »

Weather in November

November sees cold weather in Washington as the autumn season wanes steadily. The temperatures are in the average range of 30°F (-1.1°C) to 43°F (6.1°C) in the state. Spokane in the east averages between 30°F (-1.1°C) to 42°F (5.6°C), while Grayland in the west is between 40°F (4.4°C) to 53°F (11.7°C). Late fall brings significant precipitation that averages 6.2" (157mm) in the state. Weather in November »

Weather in December

December is the wettest month of the year in Washington with an average of 6.5" (165mm) of rainfall in the state. The winter is severely cold, with gray skies, ample rain, and abundant snow. The average high temperatures are in the 31°F (-0.6°C) to 41°F (5°C) range, and the average low temperatures are in the 20°F (-6.7°C) to 30°F (-1.1°C) zone. Weather in December »


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