Alexander McAllister House · Photo: Jon Roanhaus · CC BY-SA 3.0Few U.S. towns get less rain and snow than Union Gap: 9 inches a year
In January the night’s low is typically 25°. By July afternoons alone, it runs hotter than 75% of U.S. towns. Since 1901–2000, the year has warmed by 1.2°, most of all in January. The heating season runs November to March: each of those months averages under 50°.
A year in Union Gap at a glance
Each month’s typical high and low, and what it brings.
What stands out about Union Gap’s climate
Compared with towns across the U.S., with Union Gap’s place in Washington beside it.
What a year in Union Gap 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, 2.6 miles from the town’s center, at about the same height.
The 2023 USDA map puts Union Gap’s center in zone 7a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 3°. 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 9 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 Union Gap
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 Union Gap’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. 1.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Union Gap from natural hazards, earthquakes are the largest share (69%); heat waves, cold waves, winter storms and ice storms together are 8%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Union Gap and its neighbors
Every town next door is within a degree of Union Gap in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Union Gap’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 |
|---|---|---|---|---|
| Union Gap, WA | 25° | 90° | 9" | 20" |
| Gardnerville Ranchos, NV | 23° | 90° | 11" | 22" |
| Kimberly, ID | 22° | 90° | 10" | 24" |
| Snowflake, AZ | 20° | 90° | 10" | 13" |
| Redmond, OR | 25° | 86° | 9" | 22" |
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 Union Gap averaged 1.2° warmer than the 1900s. The biggest change is in January (+3.7°).
A smaller shift than in 60% 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 Union Gap compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Union Gap’s place among Washington’s.
Union Gap weather by month
Highs, lows and precipitation from NOAA’s grid at Union Gap’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° | 25° | 1.2" | 6.2" | 10 | 11 | 23° – 38° |
| February | 47° | 27° | 0.8" | 2.7" | 7 | 4 | 24° – 43° |
| March | 57° | 32° | 0.7" | 0.6" | 7 | 0 | 37° – 50° |
| April | 65° | 38° | 0.7" | 0.0" | 6 | 0 | 46° – 58° |
| May | 74° | 46° | 0.9" | 0.0" | 6 | 0 | 55° – 66° |
| June | 81° | 52° | 0.6" | 0.0" | 5 | 0 | 62° – 75° |
| July | 90° | 57° | 0.3" | 0.0" | 2 | 0 | 65° – 78° |
| August | 89° | 56° | 0.2" | 0.0" | 2 | 0 | 66° – 76° |
| September | 80° | 48° | 0.4" | 0.0" | 3 | 0 | 60° – 68° |
| October | 65° | 37° | 0.9" | 0.1" | 6 | 0 | 46° – 58° |
| November | 49° | 30° | 1.0" | 3.0" | 8 | 2 | 33° – 46° |
| December | 38° | 25° | 1.4" | 7.7" | 10 | 9 | 25° – 37° |
| Year | 64° | 39° | 8.9" | 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 Union Gap’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 Union Gap’s center.
- Snow: Yakima Air Terminal, WA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Yakima Air Terminal, WA, 2.6 miles from the town’s center, at about the same height; 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 Union Gap’s climate
What is the weather like in Union Gap?
A typical July afternoon reaches 90°, a January night drops to 25°, and about 20 inches of snow falls in a normal winter. Milder January nights than 64% of U.S. towns; hotter July afternoons than 75% of U.S. towns.
How cold does it get in Union Gap 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 Union Gap 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 Union Gap?
July, with a typical high of 90° and a low of 57°. About 40 days a year reach 90° and 6 reach 100° (Yakima Air Terminal, WA).
When is the first and last frost in Union Gap?
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 Union Gap in?
Zone 7a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 3°.
What is the best time of year to visit Union Gap?
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 Union Gap getting warmer?
Yes: 1991–2020 averaged 1.2° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 60% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Union Gap.
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.