Weather in Seattle in January

The month to avoid. Of the twelve, January is the one to avoid. Highs sit at 7.8 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

January ranks 11 of 12 — near the bottom of Seattle's year. July is the month that works, and the swing between the two is 71 points, which is a different holiday rather than a slightly better one.

Rain on 19 days, 6 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 7.8 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 7 nights fall below freezing; the day barely swings — 5.4 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest January day reached 17.9 °C and the coldest night fell to -10 °C, and the wettest single day dropped 69 mm — roughly 40% of the month's rain in one day.

January is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest January on record still delivered 333 mm against 81 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 173 mm average is a reasonable planning figure, not a promise.

Wind is light at 3 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 90%, which at 7.8 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How January sits in the year

Temperatures hold steady either side: 7 °C in December, 7.8 here, 8.7 in February. Nothing about the timing within the month matters much.

Daylight in January

January sits at the dark end of Seattle's year — 8.8 hours of daylight against 16 at midsummer, gaining 0.9 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

Despite being inland, the year stays fairly even: 21.9 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

January in Seattle versus nearby

If Seattle is one option among several, the nearby comparison is worth making. Maple Ridge is close enough to be a coin toss — within a degree on temperature, 2 days more rain. Vancouver is the weaker option in January — 3.2 °C cooler, 2 days more rain.

So: January is a compromise. July is 68 points better and is what Seattle is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Seattle

See all twelve months in Seattle, or where else to go in January.