Zillah, WA climate
Zillah has chilly winters and warm summers, with very little rain. A typical July afternoon reaches 90°, a January night drops to 27°, and about 20 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Zillah feels like
Winter
Spring
Summer
Fall
Zillah 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 | 30-yr range |
|---|---|---|---|---|---|---|
| January | 40° | 27° | 1.0" | 5.2" | 9 | 24° – 38° |
| February | 47° | 28° | 0.7" | 1.1" | 6 | 25° – 44° |
| March | 57° | 33° | 0.6" | 0.3" | 6 | 37° – 51° |
| April | 65° | 39° | 0.7" | 0 | 5 | 47° – 58° |
| May | 74° | 47° | 0.8" | 0 | 6 | 55° – 67° |
| June | 81° | 53° | 0.6" | 0 | 5 | 63° – 75° |
| July | 90° | 59° | 0.2" | 0 | 3 | 66° – 79° |
| August | 89° | 57° | 0.2" | 0 | 2 | 67° – 77° |
| September | 80° | 49° | 0.3" | 0 | 3 | 60° – 68° |
| October | 65° | 38° | 0.8" | 0.2" | 6 | 46° – 58° |
| November | 50° | 31° | 0.9" | 1.6" | 8 | 34° – 47° |
| December | 39° | 26° | 1.2" | 12.0" | 10 | 26° – 38° |
| Year | 65° | 40° | 7.9" | 20.4" | 68 |
“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 Zillah
Zillah gets 8 inches of rain and melted snow a year. December is the wettest month and July the driest. Rain or snow falls on about 68 days a year.
About 176 frost-free days a year
In half of years the last 32° night comes by April 21 and the first one by October 15. That leaves about 176 frost-free days for gardens, shorter than 53% of U.S. towns.
Heating and cooling a home in Zillah
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Zillah, 87% of that work is heating and 13% 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 Zillah 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 Zillah averaged 1.0° warmer than the 1900s. The biggest change is in January (+3.3°). The shift is smaller than in 72% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Zillah’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 25° to 44°. September is the most reliable, staying within 8°.
Common questions about Zillah’s climate
What is the coldest month in Zillah?
December, with a typical high of 39° and a low of 26°.
What is the hottest month in Zillah?
July, with a typical high of 90° and a low of 59°. About 41 days a year reach 90°.
How much snow does Zillah get?
About 20 inches in a normal winter, most of it in December.
When is the first frost in Zillah?
In half of years the first 32° night comes by October 15, and the last spring frost by April 21.
What is the rainiest month in Zillah?
December, with 1.2 inches of rain and melted snow. The year totals 8 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Zillah itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Wapato, WA (7 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.