Tumwater, WA climate
Tumwater has mild winters and pleasant summers, with plenty of rain. A typical July afternoon reaches 78°, a January night drops to 34°, and about 4 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Tumwater feels like
Winter
Spring
Summer
Fall
Tumwater weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 47° | 34° | 7.6" | 2.0" | 20 | 1 | 35° – 45° |
| February | 50° | 34° | 5.0" | 0.6" | 16 | 0 | 35° – 47° |
| March | 55° | 36° | 5.6" | 0.1" | 19 | 0 | 42° – 49° |
| April | 60° | 39° | 3.7" | 0 | 16 | 0 | 45° – 54° |
| May | 67° | 44° | 2.3" | 0 | 11 | 0 | 51° – 59° |
| June | 71° | 49° | 1.5" | 0 | 9 | 0 | 57° – 65° |
| July | 78° | 52° | 0.6" | 0 | 4 | 0 | 61° – 68° |
| August | 78° | 52° | 0.9" | 0 | 5 | 0 | 62° – 68° |
| September | 72° | 48° | 1.9" | 0 | 8 | 0 | 58° – 64° |
| October | 61° | 42° | 4.8" | 0 | 15 | 0 | 48° – 56° |
| November | 51° | 37° | 8.1" | 0 | 20 | 0 | 40° – 49° |
| December | 46° | 34° | 8.0" | 1.2" | 20 | 0 | 35° – 42° |
| Year | 61° | 42° | 50.1" | 3.9" | 163 | 2 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Tumwater
Tumwater gets 50 inches of rain and melted snow a year. November is the wettest month and July the driest. Rain or snow falls on about 163 days a year.
About 169 frost-free days a year
In half of years the last 32° night comes by April 29 and the first one by October 14. That leaves about 169 frost-free days for gardens, shorter than 62% of U.S. towns.
Heating and cooling a home in Tumwater
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Tumwater, 98% of that work is heating and 2% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Tumwater compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Tumwater averaged 0.8° warmer than the 1900s. The biggest change is in January (+2.2°). The shift is smaller than in 82% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Tumwater’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 35° to 47°. August is the most reliable, staying within 6°.
Common questions about Tumwater’s climate
What is the coldest month in Tumwater?
February, with a typical high of 50° and a low of 34°.
What is the hottest month in Tumwater?
August, with a typical high of 78° and a low of 52°. About 6 days a year reach 90°.
How much snow does Tumwater get?
About 4 inches in a normal winter, most of it in January.
When is the first frost in Tumwater?
In half of years the first 32° night comes by October 14, and the last spring frost by April 29.
What is the rainiest month in Tumwater?
November, with 8.1 inches of rain and melted snow. The year totals 50 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Tumwater itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Olympia Airport, WA (1 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.