Mattawa, WA climate
Mattawa has chilly winters and warm summers, with very little rain. A typical July afternoon reaches 91°, a January night drops to 26°, and about 10 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Mattawa feels like
Winter
Spring
Summer
Fall
Mattawa 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 | 39° | 26° | 1.0" | 3.2" | 7 | 9 | 24° – 38° |
| February | 46° | 29° | 0.7" | 1.2" | 5 | 2 | 27° – 44° |
| March | 57° | 34° | 0.6" | 0.4" | 5 | 0 | 39° – 51° |
| April | 65° | 40° | 0.5" | 0 | 5 | 0 | 48° – 59° |
| May | 75° | 48° | 0.6" | 0 | 6 | 0 | 57° – 66° |
| June | 82° | 55° | 0.5" | 0 | 4 | 0 | 64° – 76° |
| July | 91° | 61° | 0.2" | 0 | 2 | 0 | 69° – 80° |
| August | 89° | 59° | 0.1" | 0 | 2 | 0 | 69° – 77° |
| September | 80° | 51° | 0.2" | 0 | 3 | 0 | 62° – 69° |
| October | 65° | 40° | 0.5" | 0 | 6 | 0 | 48° – 58° |
| November | 49° | 32° | 0.8" | 1.7" | 7 | 1 | 34° – 46° |
| December | 39° | 26° | 1.2" | 3.4" | 8 | 7 | 26° – 37° |
| Year | 65° | 42° | 7.0" | 9.9" | 59 | 20 |
“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 Mattawa
Mattawa gets 7 inches of rain and melted snow a year. December is the wettest month and August the driest. Rain or snow falls on about 59 days a year. Snow covers the ground about 20 days of the year.
About 222 frost-free days a year
In half of years the last 32° night comes by March 24 and the first one by November 4. That leaves about 222 frost-free days for gardens, longer than 83% of U.S. towns.
Heating and cooling a home in Mattawa
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Mattawa, 78% of that work is heating and 22% is cooling.
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 Mattawa 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 Mattawa averaged 0.9° warmer than the 1900s. The biggest change is in January (+3.3°). The shift is smaller than in 77% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Mattawa’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 27° to 44°. September is the most reliable, staying within 7°.
Common questions about Mattawa’s climate
What is the coldest month in Mattawa?
January, with a typical high of 39° and a low of 26°.
What is the hottest month in Mattawa?
July, with a typical high of 91° and a low of 61°. About 50 days a year reach 90°.
How much snow does Mattawa get?
About 10 inches in a normal winter, most of it in December.
When is the first frost in Mattawa?
In half of years the first 32° night comes by November 4, and the last spring frost by March 24.
What is the rainiest month in Mattawa?
December, with 1.2 inches of rain and melted snow. The year totals 7 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Mattawa itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Moxee City 10 E, WA (20 mi, snow) and Priest Rapids Dam, WA (6 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.