Washington, USA
Long-term weather forecast
Long-term weather forecast

Monthly weather forecast and climate
Seattle, WA

Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington
Beautiful dusk skyline over the giant skyscrapers of Seattle, Washington
Seattle, the largest city in the Washington State, has a warm, temperate oceanic climate (Köppen climatic classification Cfb) characterized by cool, wet winters and mild, relatively dry summers. The city is located in the lowland area of Puget Sounds between the Olympic Mountains and the Cascade Mountains and is the cloudiest region in the United States. The climate of Seattle is influenced by the dry winds from the slopes of the Cascade Mountains and the Fraser Valley.

Summertime is mildly warm and moderately dry with pleasant temperatures ranging between 68°F (20°C) and 73.4°F (23°C) and a tolerable average humidity of 66.1%. The lovely blue skies, minimal rainfall, and extended daylight hours up to sixteen hours increase the enjoyment of summer.

Winters in Seattle are cold and wet. Rainfall is experienced for an average of eighteen days per month, and the rain gauge collects approximately 5.8" (147.3mm). Snow is not uncommon, accumulating up to 1.7" (43.2mm), mostly in December and February. Humidity averages 79% across the season, and the average sunshine hours per day are two.

Spring and autumn have mildly cold temperatures and moderately rainy days. The skies remain somewhat cloudy, and most days are pleasantly warm and sunny.
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The best time to visit Seattle is during the summer, from mid-May to September. The temperatures are warm and pleasant with lows of 53.6°F (12°C) and highs of 73.4°F (23°C).
The sea temperatures are favorable at 57.2°F (14°C). Summers are devoid of the excess winter rainfall and have elongated days making it the best time to tour Seattle. Humidity is tolerable hence the stays are lovely and less sticky.
The Seattle International Film Festival should be a must-go with occasional street displays of popular films. The hotels may be costly, but early booking and reservation guarantee the best prices.

Winter is not the best time to visit Seattle. With extremely low temperatures between 35.6°F (2°C) and 50°F (10°C), outdoor might be almost impossible even for the strong-willed. Most activities are redirected to indoors owing to the chilly winds blowing all the time. Winter experiences the highest rainfall, so most days are bound to be wet and slippery. Snow falls are high and regular accumulating up to 1.7" (43.2mm), and apart from skiing and snow skating, winter has limited activities to enjoy in Seattle.

Owing to its geographical location in the Puget Sound area, Seattle remains susceptible to windstorms and ice storms, which may result in felled trees, which in turn result in great property damage, especially the power lines.
Seattle is lowly placed, and as such, the high rainfall in winter poses a possible flood threat primarily in the lower parts of the city.

January is the coldest month with 78% humidity and extremely low temperatures in the range of 35.6°F (2°C) to 44.6°F (7°C) accompanied by one and a half days of snowing and a resultant 1.4" (35.6mm) of snowfall. Weather in January »

February is still a cold month, and it comes with a decrease in humidity to 75% and an increase in the temperatures to the range of 37.4°F (3°C) and 50°F (10°C). Snowfall reduces to only one day on average. Weather in February »

March is the start of spring in Seattle. It is characterized by a further drop in humidity to 73.1% and a significant rise in temperatures to the range of 37.4°F (3°C) and 53.6°F (12°C) making the weather warmer and more pleasant, especially with the five daily hours of sunshine. Weather in March »

The temperatures are mildly warmer and more pleasant in the range of 41°F (5°C) and 57.2°F (14°C), and there is a further drop in relative humidity to 70.8%. Weather in April »

May is the loveliest month in Seattle as the days begin to become longer than nights. Temperatures rise to a moderately warm range of 46.4°F (8°C) to 64.4°F (18°C). Weather in May »

Summer begins officially in June bringing with it a tolerable 66.8% humidity and warmer temperatures in the range of 51.8°F (11°C) and 69.8°F (21°C). Weather in June »

Temperatures are the most pleasant in the range of 55.4°F (13°C), and 73.4°F (23°C) and touring Seattle becomes most comfortable, especially with sixteen hours of daylight. Weather in July »

August remains moderately warm and pleasant with the temperatures in the range of 55.4°F (13°C) and 73.4°F (23°C), but witnesses significant rise in humidity to 68%. Weather in August »

September is transitional month and experiences summer weather only for the first few weeks. With a significant rise in humidity to 72.9%, temperatures in September cool to the range of 51.8°F (11°C) and 68°F (20°C) as autumn arrives. Weather in September »

Mildly warm and pleasant temperatures in the range of 46.4°F (8°C) and 60.8°F (16°C) make desirable touring the beautiful parks under the mildly cloudy skies. Weather in October »

November temperatures cool down considerably, to a mildly low range of 41°F (5°C) and 51.8°F (11°C) bringing along high rainfall of up to 5.7" (144.8mm) precipitation. Weather in November »

Winter sets in December with the highest humidity of 81% and extremely low temperatures in the range of 35.6°F (2°C) and 46.4°F (8°C) making Seattle cold and an icy city with the constantly blowing winds. Weather in December »

The month with the highest number of rainy days is November (18.4 days).
The month with the lowest number of rainy days is August (4.8 days).

Months with the highest snowfall are February and December (1.7").
Months with the lowest snowfall are April, May, June, July, August, September and October (0").

The month with the highest number of snowfall days is December (1.6 days).
Months with the lowest number of snowfall days are April, May, June, July, August, September and October (0 days).

The best month for swimming (with the highest average sea temperature) is August (53.5°F).
The coldest month (with the lowest average sea temperature) is February (45.3°F).