Seattle averages 226 cloudy days a year and about 53 hours of sunshine in December, roughly a fifth of what the sun could give if the sky were clear. On the shortest day the sun is up for just under eight and a half hours and climbs only 19 degrees above the horizon at noon. Here is the Seattle year in numbers, month by month, from official weather data.
How grey is Seattle, really?
NOAA's Comparative Climatic Data counts 226 cloudy days a year at Seattle, more than Buffalo (208) or Pittsburgh (203). Portland is close behind at 222. Add the partly cloudy days and cloud covers more than a quarter of the sky on about 308 days a year, which leaves roughly 57 clear days. See where Seattle ranks among the cloudiest cities in the US.
| Seattle at a glance | Figure |
|---|---|
| Latitude (Sea-Tac Airport) | 47.4°N |
| Cloudy days a year | 226 |
| Days with measurable rain (0.01 in or more) | 156 |
| Sunshine hours a year | 2,170 |
| December sunshine hours | 53 (20% of possible) |
| Shortest day (21 Dec 2026) | 8 h 25 min, sunrise 7:54 am, sunset 4:20 pm |
| Sun height at noon on the shortest day | 19° |
What does a Seattle year look like month by month?
| Month | Sunshine hours | % of possible sunshine | Days with rain |
|---|---|---|---|
| January | 70 | 25% | 18.7 |
| February | 109 | 38% | 15.9 |
| March | 178 | 48% | 17.1 |
| April | 207 | 51% | 15.0 |
| May | 254 | 54% | 11.3 |
| June | 268 | 56% | 9.2 |
| July | 312 | 65% | 4.7 |
| August | 281 | 64% | 4.9 |
| September | 222 | 59% | 8.3 |
| October | 143 | 42% | 14.3 |
| November | 73 | 26% | 18.4 |
| December | 53 | 20% | 18.4 |
The grey stretch runs from November to January, when Seattle gets about a quarter of its possible sunshine or less and it rains on more than half of all days. July is the opposite story, with 312 hours of sun and fewer than five rainy days.
What is Seattle weather like in November?
November is when Seattle's grey season really sets in. It averages about 73 hours of sunshine, roughly a quarter of what a clear sky would give, and it rains on about 18 of its 30 days. That is about half of October's 143 hours of sun.
The days shrink fast too. Clocks go back on 1 November, and sunset moves from 4:51 pm that day to 4:20 pm by the 30th. Across the month Seattle loses more than an hour of daylight, from just under 10 hours to about 8 hours and 45 minutes, and the noon sun drops from 28 to 21 degrees above the horizon.
If you are visiting, bring a waterproof layer and plan time outside around midday. If you live here, November is a good month to settle into a daily routine before December, the darkest month of the year.
Ray™'s November plan: get outside in the daylight while you can, keep a list of things to do on a rainy day in Seattle, and build your mornings around our grey-day morning routine.
What is Seattle weather like in December?
December is Seattle's darkest month. It averages about 53 hours of sunshine, just 20% of what a clear sky would give, and it rains on about 18 of its 31 days. The days are the shortest of the year too. On 21 December the sun rises at 7:54 am, sets at 4:20 pm and climbs only 19 degrees above the horizon at noon.
Most of that rain is light and steady rather than heavy. It is the low cloud, the short days and the weak sun together that make a Seattle December feel so grey. If you are visiting, pack a waterproof layer and plan time outside around midday, when the light is best. If you live here, it is the month to lean on a daily routine that does not depend on the weather.
Ray™'s December plan: step outside around lunchtime, keep your mornings steady with our grey-day morning routine, and read our guide to vitamin D in Pacific Northwest winters.
Does it rain a lot in Seattle?
Often, but not much. Seattle is not the rainiest city in the US. It gets about 39 inches of rain a year, less than many East Coast and Gulf Coast cities. What sets it apart is how often it rains and how much cloud there is. Light rain on 156 days a year, under low cloud, is what makes a Seattle winter feel grey.
When is the rainy season in Seattle?
Seattle's rainy season runs from October through April. In each of those months it rains on 14 days or more, peaking at about 19 rainy days in January. May eases off to about 11, and July and August are the dry months, with fewer than five rainy days each. If you are here in the wet months, our guide to things to do on a rainy day in Seattle has a plan for morning, afternoon and evening.
Can you make vitamin D from the sun in a Seattle winter?
Research from Boston (42°N) found skin made no vitamin D from sunlight from November through February, and at 52°N the gap ran from October through March (Webb, Kline and Holick, 1988). Seattle sits between the two, and in December the noon sun reaches only 19 degrees. Our guide to vitamin D in Pacific Northwest winters covers how much adults need and where to get it.
FAQ
How many cloudy days does Seattle get a year?
About 226, based on NOAA's Comparative Climatic Data for Seattle.
How many sunny days does Seattle get?
Roughly 57 clear days a year. Cloud covers more than a quarter of the sky on the other 308 or so.
What is the darkest month in Seattle?
December, with about 53 hours of sunshine and the shortest days of the year.
Ray™'s take: You can't change the forecast. You can plan for it. Start with our Morning, Afternoon and Evening lineups, or see how Seattle compares in The Grey Index.
Sources and method
Cloudy and partly cloudy days: NOAA Comparative Climatic Data, Seattle, averaged over the station's period of record. Sunshine hours and percentage of possible sunshine: NOAA averages for Sea-Tac Airport, 1961 to 1990, the latest period NOAA published before its sunshine sensors were retired. Days with rain and annual rainfall: NOAA 1991 to 2020 normals for Sea-Tac Airport. Sunrise, sunset and sun height for 21 December 2026: timeanddate.com. November 2026 sunrise, sunset, day length and noon sun height: timeanddate.com. This page is for education and is not medical advice.