Photo: Scott A. Johnson · CC BY-SA 2.5Few U.S. towns have colder winter nights than Glennallen
Sunny July days climb to about 69°. Summers stay cool: July afternoons here are cooler than in almost every U.S. town. Only 81° separates winter nights from summer afternoons. Seedlings are safe outdoors from about June 7, with the first autumn frost due around August 21.
A year in Glennallen at a glance
Each month’s typical high and low, and what it brings.
What stands out about Glennallen’s climate
Compared with towns across the U.S., with Glennallen’s place in Alaska beside it.
What a year in Glennallen feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 73 frost-free days a year
In half of years the last 32° night comes by June 7 and the first by August 21. Frost and day counts come from NOAA’s station at Gulkana Airport, 12 miles from the town’s center, 480 ft lower.
The 2023 USDA map puts Glennallen’s center in zone 3a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −40°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 12 inches of rain a year
August is the wettest month and April the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Glennallen
Nearly all of the work is heating: a normal year has almost no cooling days. Months averaging under 55°: every month but July.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Gulkana Airport.
Living with Glennallen’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
73 frost-free days in zone 3a. The last frost comes by Jun 7 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Aug 21.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 3.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Glennallen from natural hazards, avalanches are the largest share (76%); heat waves, cold waves, winter storms and ice storms together are 3%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Glennallen and its neighbors
Tolsona has the coldest January nights next door (-14°, 3° colder). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
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 Glennallen compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Glennallen’s place among Alaska’s.
Glennallen weather by month
Highs, lows and precipitation from the nearest NOAA station. 1991–2020 normals.
| Month | High | Low | Rain + melt |
|---|---|---|---|
| January | 5° | −12° | 0.7" |
| February | 16° | −5° | 0.7" |
| March | 28° | 1° | 0.3" |
| April | 44° | 21° | 0.2" |
| May | 58° | 33° | 0.8" |
| June | 67° | 43° | 1.4" |
| July | 69° | 47° | 1.7" |
| August | 65° | 43° | 1.9" |
| September | 54° | 33° | 1.4" |
| October | 36° | 18° | 1.0" |
| November | 15° | −1° | 0.9" |
| December | 8° | −8° | 0.8" |
| Year | 39° | 18° | 11.8" |
Where Glennallen’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).
- Frost, freezing nights, 90° and 100° days, heating and cooling: Gulkana Airport, 12 miles from the town’s center, 480 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.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Glennallen’s climate
What is the weather like in Glennallen?
A typical July afternoon reaches 69°, a January night drops to −12°. Colder January nights than all but 7 U.S. towns; cooler July afternoons than all but 74 U.S. towns.
How cold does it get in Glennallen in winter?
January nights average −12°. About 238 nights a year reach 32° or below and 99 reach 0° or below.
How hot does it get in Glennallen?
July, with a typical high of 69°. 90° days are rare: none in a normal year at Gulkana Airport.
When is the first and last frost in Glennallen?
In half of years the last spring frost (32°) comes by June 7 and the first fall frost by August 21, about 73 frost-free days, at Gulkana Airport.
What growing zone is Glennallen in?
Zone 3a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −40°.
What is the best time of year to visit Glennallen?
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 Glennallen.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.