Sullivan Roadhouse · Photo: Ovmalyk · CC BY-SA 3.0Hardly any U.S. towns see harsher January nights than Delta Junction
On a normal July day the thermometer tops out near 70°. Summers stay cool: July afternoons here are cooler than in almost every U.S. town. Winter and summer sit 78° apart. Tender plants can go out after about May 17; in half of years the first frost comes by September 7.
A year in Delta Junction at a glance
Each month’s typical high and low, and what it brings.
What stands out about Delta Junction’s climate
Compared with towns across the U.S., with Delta Junction’s place in Alaska beside it.
What a year in Delta Junction feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 113 frost-free days a year
In half of years the last 32° night comes by May 17 and the first by September 7. Frost and day counts come from NOAA’s station at Big Delta Airport, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Delta Junction’s center in zone 2a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −47°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 45 inches of snow a winter
Snow, measured at Delta 5 Ne, AK, is heaviest from October through December, about 8 inches a month. Precipitation (rain plus melted snow) adds up to 10 inches a year; July is the wettest month and March the driest. Rain or snow falls on about 106 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Delta Junction
Nearly all of the work is heating: a normal year has almost no cooling days. Months averaging under 55° run from September 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 Big Delta Airport.
Living with Delta Junction’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
113 frost-free days in zone 2a. The last frost comes by May 17 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 7.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 7.9 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Delta Junction from natural hazards, wildfire is the largest share (33%); heat waves, cold waves, winter storms and ice storms together are 20%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Delta Junction and its neighbors
Big Delta has the coldest January nights next door (-16°, 8° colder) and Deltana the hottest July afternoons (71°, 2° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Delta Junction’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 |
|---|---|---|---|---|
| Delta Junction, AK | −8° | 70° | 10" | 45" |
| Thief River Falls, MN | −4° | 79° | 22" | 50" |
| Superior, WI | 6° | 76° | 30" | 56" |
| Gunnison, CO | 0° | 82° | 12" | 50" |
| Grand Forks, ND | −2° | 81° | 22" | 49" |
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.
How Delta Junction compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Delta Junction’s place among Alaska’s.
Delta Junction weather by month
Highs, lows and precipitation from the nearest NOAA station; snow, wet days and snow on the ground from Delta 5 Ne, AK. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground |
|---|---|---|---|---|---|---|
| January | 6° | −8° | 0.2" | 6.1" | 7 | 31 |
| February | 16° | −1° | 0.2" | 4.6" | 5 | 27 |
| March | 25° | 4° | 0.2" | 4.0" | 5 | 30 |
| April | 44° | 24° | 0.2" | 3.1" | 4 | 13 |
| May | 59° | 38° | 0.8" | 1.7" | 8 | 0 |
| June | 68° | 49° | 2.2" | 0.1" | 12 | 0 |
| July | 70° | 52° | 2.4" | 0.0" | 15 | 0 |
| August | 65° | 47° | 2.0" | 0.0" | 15 | 0 |
| September | 53° | 36° | 0.9" | 2.3" | 10 | 1 |
| October | 33° | 20° | 0.6" | 7.3" | 8 | 16 |
| November | 15° | 1° | 0.4" | 7.8" | 9 | 29 |
| December | 9° | −5° | 0.2" | 8.0" | 8 | 30 |
| Year | 39° | 21° | 10.3" | 45.0" | 106 | 179 |
Where Delta Junction’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s 1991–2020 normals at the nearest station (NOAA’s grid doesn’t cover Alaska).
- Snow: Delta 5 Ne, AK.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Big Delta Airport, 4 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.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Delta Junction’s climate
What is the weather like in Delta Junction?
A typical July afternoon reaches 70°, a January night drops to −8°, and about 45 inches of snow falls in a normal winter. Colder January nights than all but 10 U.S. towns; cooler July afternoons than all but 78 U.S. towns.
How cold does it get in Delta Junction in winter?
January nights average −8°. About 219 nights a year reach 32° or below and 82 reach 0° or below.
How much snow does Delta Junction get?
About 45 inches in a normal winter at Delta 5 Ne, AK, heaviest from October through December, about 8 inches a month, with snow on the ground about 179 days a year.
How hot does it get in Delta Junction?
July, with a typical high of 70°. 90° days are rare: none in a normal year at Big Delta Airport.
When is the first and last frost in Delta Junction?
In half of years the last spring frost (32°) comes by May 17 and the first fall frost by September 7, about 113 frost-free days, at Big Delta Airport.
What growing zone is Delta Junction in?
Zone 2a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −47°.
What is the best time of year to visit Delta Junction?
By one simple rule (highs of 62–84° and lows of 40° or more), June, July and August. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Neighbors talk weather
Gardens, snow, and the best days of the year in Delta Junction.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.