Seattle weather in December: Seattle, Washington: normal highs, lows, rain and records for December
Seattle in December has a normal high of 47°F and a normal low of 37°F, a daily mean of 42°F, falling from 49°F on the 1st to 47°F by the 31st. Measurable precipitation falls on 18 days in a normal December, 5.72 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 8°C and low of 3°C, 145 mm of precipitation and 4 cm of snow in December.
- NOAA stationSeattle Tacoma International Airport
- Station IDUSW00024233
- Location47.44°N 122.31°W
- Elevation370 ft (113 m)
- From the center12 miles
- Population780,995
- Jan 48° 38°
- Feb 50° 38°
- Mar 54° 40°
- Apr 59° 43°
- May 66° 49°
- Jun 71° 53°
- Jul 77° 57°
- Aug 78° 57°
- Sep 72° 54°
- Oct 61° 47°
- Nov 52° 41°
- Dec 47° 37°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Seattle in December?
The normal high is 47°F and the normal low 37°F, for a daily mean of 42.0°F. December is 4.5°F cooler than November and 0.8°F cooler than January. December is the 12th warmest month of the year in Seattle and the 3rd wettest. Across the month the normal high falls 2°F, from 49°F on December 1 to 47°F on December 31. From one year to the next December's mean temperature typically moves about 2.1°F either way (NOAA's standard deviation), so roughly two Decembers in three average between 40°F and 44°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 61%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| December 1 | 49°F | 38°F | 60% | 41% |
| December 8 | 48°F | 37°F | 60% | 41% |
| December 15 | 47°F | 37°F | 61% | 41% |
| December 22 | 46°F | 37°F | 61% | 41% |
| December 31 | 47°F | 37°F | 61% | 41% |
Every day of December: normal high, low and chance of precipitation (warmest afternoon December 1, coldest night December 18)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| December 1 | 49°F | 38°F | 60% | 41% | 8 h 50 min |
| December 2 | 49°F | 38°F | 60% | 41% | 8 h 40 min |
| December 3 | 48°F | 38°F | 60% | 41% | 8 h 40 min |
| December 4 | 48°F | 38°F | 60% | 41% | 8 h 40 min |
| December 5 | 48°F | 38°F | 60% | 41% | 8 h 40 min |
| December 6 | 48°F | 38°F | 60% | 41% | 8 h 40 min |
| December 7 | 48°F | 37°F | 60% | 41% | 8 h 40 min |
| December 8 | 48°F | 37°F | 60% | 41% | 8 h 40 min |
| December 9 | 47°F | 37°F | 60% | 41% | 8 h 30 min |
| December 10 | 47°F | 37°F | 60% | 41% | 8 h 30 min |
| December 11 | 47°F | 37°F | 60% | 41% | 8 h 30 min |
| December 12 | 47°F | 37°F | 60% | 41% | 8 h 30 min |
| December 13 | 47°F | 37°F | 60% | 41% | 8 h 30 min |
| December 14 | 47°F | 37°F | 60% | 41% | 8 h 30 min |
| December 15 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 16 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 17 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 18 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 19 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 20 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 21 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 22 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 23 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 24 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 25 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 26 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 27 | 46°F | 37°F | 61% | 41% | 8 h 30 min |
| December 28 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 29 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 30 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
| December 31 | 47°F | 37°F | 61% | 41% | 8 h 30 min |
- Normal high
- 47°FDecember average
- Normal low
- 37°FDecember average
- Precipitation
- 5.72 inmonth total
- Days with precipitation
- 180.01 inch or more
- Snowfall
- 1.7 inmonth total
- Nights at 32°F or colder
- 7
- Daylight
- 8 h 50 min to 8 h 30 minDecember 1 to December 31
- Sunshine
- 51%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024233; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Seattle in December?
On a given December day the chance of 0.01 inch or more is 61% on average, highest around December 28 (61%). In all, 5.72 in falls on 18 days of a normal December, 1 of them with an inch or more.
In a normal December in Seattle, 7 nights fall to freezing, 1 days stay below freezing all day and snowfall averages 1.7 inches.
Snow falls on 2 days in a normal December, and an inch or more covers the ground on 1 day.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024233.
How humid and windy is Seattle in December?
At 3 p.m. the normal temperature is 44°F with 73% relative humidity and a dew point of 36°F; at 6 a.m. it is 39°F with 83% humidity. The wind averages 8.4 mph, most often from the south in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 39°F | 34°F | 83% | 8.0 mph | – |
| 9 a.m. | 40°F | 35°F | 81% | 8.2 mph | – |
| noon | 43°F | 36°F | 75% | 8.4 mph | – |
| 3 p.m. | 44°F | 36°F | 73% | 8.5 mph | – |
| 6 p.m. | 42°F | 36°F | 78% | 9.0 mph | – |
| 9 p.m. | 41°F | 35°F | 79% | 8.8 mph | 22% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024233. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for December in Seattle?
The warmest December temperature on this station's record (since 1945) is 66°F, on December 10, 2014; the coldest is 6°F, on December 30, 1968. The wettest December brought 11.85 in (1979); the snowiest, 22.1 inches (1968).
The December mean against the 1991-2020 normal of 42.0°F: 2021 38.0°F (−4.0), 2022 38.8°F (−3.2), 2023 45.5°F (+3.5), 2024 44.2°F (+2.2), 2025 45.2°F (+3.2). 3 of 5 ran warmer than normal.
| December | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 38.0°F | −4.0°F | 4.08 in |
| 2022 | 38.8°F | −3.2°F | 7.55 in |
| 2023 | 45.5°F | +3.5°F | 8.48 in |
| 2024 | 44.2°F | +2.2°F | 5.49 in |
| 2025 | 45.2°F | +3.2°F | 7.37 in |
Source: records: ACIS, station USW00024233; recent months: ACIS, station USW00024233. Records and recent months use complete months only.
How does December in Seattle compare across Washington?
Across the 96 places PlainClimate covers in Washington, December normal highs run from 29°F in Winthrop to 48°F in Grayland; Seattle's is 47°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.