Ahtanum sits near the bottom of U.S. towns for precipitation, with 10 inches a year
July afternoons average 89°. Rain follows the seasons: December brings about 11 times as much as August. Summer afternoons here are warmer than in 71% of U.S. towns. Warm coats and heating bills mark the months from November to March, when means dip under 50°.
A year in Ahtanum at a glance
Each month’s typical high and low, and what it brings.
What stands out about Ahtanum’s climate
Compared with towns across the U.S., with Ahtanum’s place in Washington beside it.
What a year in Ahtanum feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 149 frost-free days a year
In half of years the last 32° night comes by May 8 and the first by October 4. Frost and day counts come from NOAA’s station at Yakima Air Terminal, WA, 3 miles from the town’s center, 180 ft lower.
The 2023 USDA map puts Ahtanum’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 2°. 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 20 inches of snow a winter
Snow, measured at Yakima Air Terminal, WA, falls mostly in December. Precipitation (rain plus melted snow) adds up to 10 inches a year; December is the wettest month and August the driest. Rain or snow falls on about 72 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Ahtanum
90% 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 Yakima Air Terminal, WA.
Living with Ahtanum’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
149 frost-free days in zone 7a. The last frost comes by May 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 Oct 4.
Months with highs of 62–84° and lows of 40° or more: May, June and September.
Parks & trails →Of the yearly building losses FEMA expects in Ahtanum from natural hazards, river flooding is the largest share (32%); heat waves, cold waves, winter storms and ice storms together are 14%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Ahtanum and its neighbors
Every town next door is within a degree of Ahtanum in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Ahtanum’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 |
|---|---|---|---|---|
| Ahtanum, WA | 26° | 89° | 10" | 20" |
| Cold Springs, NV | 23° | 88° | 13" | 17" |
| Kimberly, ID | 22° | 90° | 10" | 24" |
| Redmond, OR | 25° | 86° | 9" | 22" |
| Silver City, NM | 26° | 87° | 16" | 13" |
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 Ahtanum averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.9°).
A smaller shift than in 53% 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.
How Ahtanum compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Ahtanum’s place among Washington’s.
Ahtanum weather by month
Highs, lows and precipitation from NOAA’s grid at Ahtanum’s center; snow, wet days and snow on the ground from Yakima Air Terminal, WA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 39° | 26° | 1.5" | 6.2" | 10 | 11 | 24° – 38° |
| February | 46° | 27° | 1.1" | 2.7" | 7 | 4 | 24° – 43° |
| March | 56° | 32° | 0.9" | 0.6" | 7 | 0 | 36° – 50° |
| April | 64° | 37° | 0.7" | 0.0" | 6 | 0 | 45° – 58° |
| May | 73° | 45° | 0.7" | 0.0" | 6 | 0 | 54° – 65° |
| June | 80° | 51° | 0.5" | 0.0" | 5 | 0 | 61° – 74° |
| July | 89° | 56° | 0.2" | 0.0" | 2 | 0 | 64° – 77° |
| August | 88° | 55° | 0.2" | 0.0" | 2 | 0 | 65° – 76° |
| September | 79° | 47° | 0.3" | 0.0" | 3 | 0 | 59° – 67° |
| October | 64° | 37° | 0.9" | 0.1" | 6 | 0 | 45° – 58° |
| November | 49° | 29° | 1.3" | 3.0" | 8 | 2 | 33° – 46° |
| December | 38° | 25° | 1.9" | 7.7" | 10 | 9 | 25° – 37° |
| Year | 64° | 39° | 10.3" | 20.3" | 72 | 26 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 24° to 43°. September is the most reliable, staying within 8°.
Where Ahtanum’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 Ahtanum’s center.
- Snow: Yakima Air Terminal, WA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Yakima Air Terminal, WA, 3 miles from the town’s center, 180 ft lower; 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 Ahtanum’s climate
What is the weather like in Ahtanum?
A typical July afternoon reaches 89°, a January night drops to 26°, and about 20 inches of snow falls in a normal winter. Milder January nights than 64% of U.S. towns; hotter July afternoons than 71% of U.S. towns.
How cold does it get in Ahtanum in winter?
December nights average 25°. About 147 nights a year reach 32° or below and 2 reach 0° or below. In the coldest December of the last 30 years the month averaged 25°.
How much snow does Ahtanum get?
About 20 inches in a normal winter at Yakima Air Terminal, WA, most of it in December, with snow on the ground about 26 days a year.
How hot does it get in Ahtanum?
July, with a typical high of 89° and a low of 56°. About 40 days a year reach 90° and 6 reach 100° (Yakima Air Terminal, WA).
When is the first and last frost in Ahtanum?
In half of years the last spring frost (32°) comes by May 8 and the first fall frost by October 4, about 149 frost-free days, at Yakima Air Terminal, WA.
What growing zone is Ahtanum in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 2°.
What is the best time of year to visit Ahtanum?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Ahtanum getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Ahtanum.
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.