Seattle features a temperate climate with cool, wet winters and short, warm, dry summers. The city is known for its frequent light rain, abundant clouds, and mild temperature swings. Summer brings long daylight hours and sunshine, while winter is marked by drizzle, overcast skies, and occasional snow, making Seattle a dynamic destination in every season.
The best times to travel section shows how the months compare for a visit, so you can find the time of year that fits what you want to do.
Background colours of the months:
The colour shows the typical temperature: yellow (hot), green (mild) and blue (cold). How strong the colour is shows the travel season: full colour means high season, soft colour means shoulder season and soft-striped means off season.
Weather symbols:
Each month has one symbol showing what the weather is typically like, such as hot and sunny, freezing or a rainy or snowy season. Use them to quickly spot months that match the weather you want, or to avoid the ones that don't.
Crowdedness:
The people icon shows how busy the place usually is. The more people, the more crowded it gets.
Additional notes:
The grey info boxes point out special things worth knowing, like recurring weather issues or seasonal events.
Seattle’s climate is classified as temperate, with a warm-summer Mediterranean influence. Winters (November–March) are cool and wet, with average highs of 8–12°C and lows near 2–5°C. Rainfall is frequent but usually light, often falling as drizzle or mist, and the city experiences more rainy days than most major U.S. cities. Snow is possible but rare, averaging about 16 cm per year, and heavy snowfalls are uncommon. Days are short and often cloudy, with December and January seeing the least sunshine.
Summers (June–September) are short, warm, and dry, with average highs of 21–25°C and lows around 12–14°C. Rain is infrequent, and July and August are the sunniest, driest months, with only 4–6 rainy days each. Sunshine can reach up to 9–10 hours per day in midsummer, and daylight lasts up to 16 hours. Spring (March–May) and autumn (September–November) are transitional, with variable weather – mild temperatures, occasional rain, and blooming or colourful foliage. Winds are generally light to moderate (10–18 km/h), but can be brisk during storms, especially in winter. The Pacific Ocean moderates temperature extremes, keeping summers cooler and winters milder than inland cities. Annual precipitation averages around 1,000 mm, with the wettest months from November to January and the driest in July. Marine fog is common in spring and early summer, while the Puget Sound and nearby mountains create microclimates across the region.
| Average climate data for Seattle, United States | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 7 | 8 | 10 | 14 | 18 | 21 | 24 | 25 | 21 | 15 | 9 | 7 | 25 |
| Average minimum temperature (°C) | 2 | 2 | 3 | 5 | 7 | 9 | 11 | 12 | 10 | 8 | 4 | 2 | 2 |
| Average precipitation (mm) | 18 | 15 | 9 | 10 | 10 | 6 | 3 | 3 | 7 | 13 | 16 | 22 | 132 |
| Average rainfall days (days) | 9 | 8 | 9 | 8 | 7 | 5 | 4 | 3 | 6 | 7 | 9 | 9 | 84 |
| Average snowfall (mm) | 3 | 18 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 24 |
| Average snowfall days (days) | 1 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 5 |
| Average relative humidity (%) | 86 | 83 | 82 | 80 | 74 | 73 | 70 | 69 | 75 | 78 | 85 | 83 | 78 |
| Average wind speed (km/h) | 8 | 8 | 8 | 8 | 6 | 6 | 6 | 6 | 6 | 7 | 8 | 8 | 7 |
| Average water temperature (°C) | 8 | 7 | 8 | 8 | 8 | 9 | 10 | 12 | 12 | 10 | 9 | 8 | 9 |
| Average daily daylight hours (h) | 9 | 10 | 11 | 13 | 15 | 15 | 15 | 14 | 12 | 10 | 9 | 8 | 12 |
| Average daily sunshine hours (h) | 4 | 4 | 6 | 8 | 9 | 9 | 10 | 10 | 9 | 5 | 4 | 4 | 7 |
| Average cloud coverage (%) | 54 | 53 | 51 | 49 | 42 | 41 | 26 | 25 | 33 | 40 | 52 | 56 | 44 |
| Average UV index | 2 | 2 | 3 | 3 | 4 | 5 | 6 | 4 | 4 | 3 | 2 | 2 | 3 |
The best time to visit Seattle is from July to September, when the weather is reliably warm (21–25°C), dry, and sunny. These months offer ideal conditions for outdoor activities, hiking, and enjoying the city’s festivals and waterfront. May, June, and early October are also pleasant, with fewer crowds and mild weather, though rain is more likely.
The least favourable time to visit is from mid-November to February, when Seattle is at its wettest, days are shortest, and skies are often overcast. While winters are mild compared to much of the U.S., frequent drizzle, chilly temperatures, and limited daylight can make outdoor exploration less appealing.
Seattle has a temperate climate with cool, wet winters and short, warm, dry summers. Rain falls frequently from October to May, while July and August are the sunniest, driest months.
Seattle is known for frequent rain, with about 150 rainy days per year. However, most rain is light drizzle or mist, and the total annual rainfall (about 1,000 mm) is less than in many other U.S. cities.
Summer temperatures in Seattle usually reach 21–25°C, with occasional heatwaves pushing highs above 30°C. Nights are cool, and humidity is low, making summer comfortable for outdoor activities.
Snow is rare in Seattle, averaging about 16 cm per year. When it does snow, it’s usually light and melts quickly, but occasional storms can bring heavier accumulations.
The rainiest season is from November to January, with frequent drizzle and overcast skies. July and August are the driest, with only a few rainy days each month.
Pack layers, a waterproof jacket, and water-resistant shoes. Even in summer, bring a jumper for cool evenings. An umbrella is useful year-round, and sunglasses are handy for sunny summer days.
Seattle is moderately windy, especially during winter storms. Humidity is generally moderate, but can feel higher during rainy months. Coastal fog is common in spring and early summer.
The warmest month, with the highest average maximum temperature, is August (24.5 °C). The month with the lowest average maximum temperature is December (6.6 °C). Overall, the average maximum temperature over the whole year is 14.9 °C.
The month with the highest average minimum temperature is August (12.3 °C). The coldest month, with the lowest average minimum temperature, is December (1.6 °C). Overall, the average minimum temperature over the whole year is 6.2 °C.
The month with the highest average water temperature is August (12.1 °C). The month with the lowest average water temperature is February (7.3 °C). Overall, the average water temperature over the whole year is 9.1 °C.
The wettest month, with the highest amount of precipitation, is December (22.1 mm). The driest month, with the least amount of precipitation, is August (3 mm). Over the whole year there are 132.3 mm of rainfall on average.
The month with the most days of rain is November (9 days). The month with the fewest days of rain is August (2.7 days). Over the whole year there are 84.2 days of rain on average.
The month with the most snowfall is February (17.9 mm). The months with the least snowfall are April, May, June, July, August, September, October and December (0 mm). Over the whole year there are 23.9 mm of snowfall on average.
The month with the most days of snowfall is February (1.9 days). The months with the fewest days of snowfall are May, June, July and September (0 days). Over the whole year there are 4.7 days of snowfall on average.
The month with the highest average relative humidity is January (86.2 %). The month with the lowest average relative humidity is August (69.2 %). The overall average relative humidity over the whole year is 78.1 %.
The windiest month, with the highest average wind speed, is March (8.5 km/h). The calmest month, with the lowest average wind speed, is August (5.6 km/h). The overall average wind speed over the whole year is 7.2 km/h.
The month with the cloudiest skies, so the highest cloud coverage, is December (56.1 %). The month with the clearest skies, so the lowest cloud coverage, is August (24.8 %). Over the whole year there is an average cloud coverage of 43.5 %.
The month with the longest days, so the most daylight, is June (Average daylight: 15.1 h). The month with the shortest days, so the least daylight, is December (Average daylight: 8 h). Over the whole year there are 11.8 h of daylight per day on average.
The month with the most sunshine per day is August (Average sunshine: 10.2 h). The month with the least sunshine per day is January (Average sunshine: 3.9 h). Over the whole year there are 6.9 h of sunlight per day on average.
The month with the highest average UV index is July (UV index: 6). The months with the lowest average UV index are January, February, November and December (UV index: 2). Over the whole year the average UV index is 3.3.
