Photo: Jeffery Hayes · CC BY-SA 3.0Hardly any U.S. towns see fresher July days than Seattle
In January the night’s low is typically 37°. Winters are mild: January nights here are milder than in 84% of U.S. towns. The latest 30-year average runs 1.3° warmer than 1901–2000’s, with January up the most. Warm coats and heating bills mark the months from November to March, when means dip under 50°.
A year in Seattle at a glance
Each month’s typical high and low, and what it brings.
What stands out about Seattle’s climate
Compared with towns across the U.S., with Seattle’s place in Washington beside it.
What a year in Seattle feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 259 frost-free days a year
In half of years the last 32° night comes by March 8 and the first by November 23. Frost and day counts come from NOAA’s station at Seattle Sand Pt Wsfo, WA, 6 miles from the city’s center point, at about the same height.
The 2023 USDA map puts Seattle’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 23°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 4 inches of snow a winter
Snow, measured at Seattle Sand Pt Wsfo, WA, falls mostly in December. Precipitation (rain plus melted snow) adds up to 38 inches a year; November is the wettest month and July the driest. Rain or snow falls on about 163 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Seattle
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Seattle Sand Pt Wsfo, WA.
Living with Seattle’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
259 frost-free days in zone 9a. The last frost comes by Mar 8 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 23.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 194 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Seattle from natural hazards, earthquakes are the largest share (80%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Seattle and its neighbors
Every town next door is within a degree of Seattle in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Seattle’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Seattle, WA | 37° | 77° | 38" | 3.8" |
| Fairfax, CA | 41° | 76° | 38" | 0.0" |
| Garden Home-Whitford, OR | 36° | 81° | 40" | 3.6" |
| Nantucket, MA | 26° | 76° | 44" | 25" |
| Brigantine, NJ | 28° | 83° | 45" | 10" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Seattle averaged 1.3° warmer than the 1900s. The biggest change is in January (+2.6°).
A smaller shift than in 58% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods. In a city of 785,000 people, part of the change is the city itself: pavement and buildings hold heat (the urban heat island).
How Seattle compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Seattle’s place among Washington’s.
Seattle weather by month
Highs, lows and precipitation from NOAA’s grid at Seattle’s center; snow, wet days and snow on the ground from Seattle Sand Pt Wsfo, WA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 48° | 37° | 5.2" | 0.9" | 19 | 1 | 38° – 46° |
| February | 50° | 37° | 3.7" | 1.0" | 16 | 1 | 37° – 49° |
| March | 55° | 39° | 4.2" | 0.0" | 18 | 0 | 42° – 51° |
| April | 60° | 42° | 3.0" | 0.0" | 16 | 0 | 47° – 56° |
| May | 66° | 48° | 2.0" | 0.0" | 12 | 0 | 53° – 61° |
| June | 71° | 52° | 1.5" | 0.0" | 11 | 0 | 58° – 67° |
| July | 77° | 56° | 0.7" | 0.0" | 5 | 0 | 62° – 71° |
| August | 77° | 56° | 1.0" | 0.0" | 6 | 0 | 62° – 69° |
| September | 71° | 52° | 1.6" | 0.0" | 9 | 0 | 59° – 65° |
| October | 61° | 46° | 3.7" | 0.0" | 15 | 0 | 50° – 58° |
| November | 52° | 40° | 5.8" | 0.2" | 19 | 0 | 42° – 51° |
| December | 46° | 36° | 5.6" | 1.7" | 20 | 1 | 37° – 45° |
| Year | 61° | 45° | 38.0" | 3.8" | 163 | 2 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 37° to 49°. September is the most reliable, staying within 6°.
Where Seattle’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Seattle’s center.
- Snow: Seattle Sand Pt Wsfo, WA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Seattle Sand Pt Wsfo, WA, 6 miles from the city’s center point, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Seattle’s climate
What is the weather like in Seattle?
A typical July afternoon reaches 77°, a January night drops to 37°, and about 4 inches of snow falls in a normal winter. Milder January nights than 84% of U.S. towns; cooler July afternoons than 97% of U.S. towns.
How cold does it get in Seattle in winter?
December nights average 36°. About 25 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 37°.
How much snow does Seattle get?
About 3.8 inches in a normal winter at Seattle Sand Pt Wsfo, WA, most of it in December, with snow on the ground about 2 days a year.
How hot does it get in Seattle?
July, with a typical high of 77° and a low of 56°. About 2 days a year reach 90° (Seattle Sand Pt Wsfo, WA).
When is the first and last frost in Seattle?
In half of years the last spring frost (32°) comes by March 8 and the first fall frost by November 23, about 259 frost-free days, at Seattle Sand Pt Wsfo, WA.
What growing zone is Seattle in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 23°.
What is the best time of year to visit Seattle?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Seattle getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 58% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Seattle.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.