Photo: A.Davey from Portland, Oregon, EE UU · CC BY 2.0Precipitation in Union trails that of 91% of U.S. towns: 17 inches a year
On a normal July day the thermometer tops out near 87°. From frosty January to warm July, readings climb 64°. In July, afternoons here are warmer than in 63% of U.S. towns. The heating season runs October to April: each of those months averages under 50°.
A year in Union at a glance
Each month’s typical high and low, and what it brings.
What stands out about Union’s climate
Compared with towns across the U.S., with Union’s place in Oregon beside it.
What a year in Union feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 136 frost-free days a year
In half of years the last 32° night comes by May 11 and the first by September 26. Frost and day counts come from NOAA’s station at Union, OR, 0.7 miles from the town’s center, at about the same height.
The 2023 USDA map puts Union’s center in zone 6b: 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 16 inches of snow a winter
Snow, measured at Union, OR, falls mostly in January and December. Precipitation (rain plus melted snow) adds up to 17 inches a year; May is the wettest month and July the driest. Rain or snow falls on about 115 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Union
94% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Union, OR.
Living with Union’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
136 frost-free days in zone 6b. The last frost comes by May 11 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Sep 26.
Months with highs of 62–84° and lows of 40° or more: May, June and September. 0.2 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Union from natural hazards, avalanches are the largest share (35%); heat waves, cold waves, winter storms and ice storms together are 25%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Union and similar climates
TownRatings has no climate map of the towns around Union yet.
Climates most like Union’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, OR | 24° | 87° | 17" | 16" |
| Silver City, NM | 26° | 87° | 16" | 13" |
| Indian Hills, NV | 25° | 86° | 14" | 14" |
| Show Low, AZ | 19° | 86° | 15" | 19" |
| Hamilton, MT | 20° | 86° | 13" | 17" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Union averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.3°).
A smaller shift than in 55% 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 compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Union’s place among Oregon’s.
Union weather by month
Highs, lows and precipitation from NOAA’s grid at Union’s center; snow, wet days and snow on the ground from Union, OR. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 40° | 24° | 1.7" | 5.3" | 13 | 10 | 24° – 37° |
| February | 44° | 26° | 1.3" | 2.9" | 10 | 6 | 28° – 42° |
| March | 53° | 30° | 1.7" | 1.2" | 11 | 1 | 36° – 46° |
| April | 60° | 33° | 1.9" | 0.4" | 13 | 0 | 42° – 53° |
| May | 69° | 40° | 2.5" | 0.1" | 13 | 0 | 49° – 59° |
| June | 76° | 45° | 1.6" | 0.0" | 10 | 0 | 57° – 68° |
| July | 87° | 50° | 0.5" | 0.0" | 4 | 0 | 59° – 74° |
| August | 87° | 49° | 0.5" | 0.0" | 4 | 0 | 63° – 71° |
| September | 78° | 41° | 0.7" | 0.0" | 5 | 0 | 56° – 64° |
| October | 63° | 34° | 1.4" | 0.0" | 9 | 0 | 42° – 54° |
| November | 48° | 29° | 1.8" | 1.4" | 13 | 1 | 32° – 45° |
| December | 39° | 23° | 1.8" | 4.9" | 12 | 8 | 25° – 35° |
| Year | 62° | 35° | 17.4" | 16.2" | 115 | 26 |
How much a month can swing
A normal is an average. July swings the most: from 1991 to 2020 its average ranged from 59° to 74°. August is the most reliable, staying within 8°.
Where Union’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’s center.
- Snow: Union, OR (NOAA station in town).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Union, OR, 0.7 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’s climate
What is the weather like in Union?
A typical July afternoon reaches 87°, a January night drops to 24°, and about 16 inches of snow falls in a normal winter. Milder January nights than 60% of U.S. towns; hotter July afternoons than 63% of U.S. towns.
How cold does it get in Union in winter?
December nights average 23°. About 135 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 get?
About 16 inches in a normal winter at Union, OR, most of it in January and December, with snow on the ground about 26 days a year.
How hot does it get in Union?
July, with a typical high of 87° and a low of 50°. About 29 days a year reach 90° and 2 reach 100° (Union, OR).
When is the first and last frost in Union?
In half of years the last spring frost (32°) comes by May 11 and the first fall frost by September 26, about 136 frost-free days, at Union, OR.
What growing zone is Union in?
Zone 6b 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 Union?
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 getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 55% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Union.
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.