Iliamna’s winters are colder than most of the U.S.; July afternoons average 65°
A typical July afternoon reaches 65°, a January night drops to 12°.
A year in Iliamna at a glance
Each month’s typical high and low, and what it brings.
What stands out about Iliamna’s climate
Compared with towns across the U.S., with Iliamna’s place in Alaska beside it.
What a year in Iliamna feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 144 frost-free days a year
In half of years the last 32° night comes by May 10 and the first by October 1. Frost and day counts come from NOAA’s station at Iliamna Airport, 5 miles from the town’s center, 200 ft lower.
The 2023 USDA map puts Iliamna’s center in zone 4b: the coldest night of a typical winter, averaged over 1991–2020, reaches about −22°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 25 inches of rain a year
September is the wettest month and April the driest.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Iliamna
Nearly all of the work is heating: a normal year has almost no cooling days. Months averaging under 55° run from September through June.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Iliamna Airport.
Living with Iliamna’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
144 frost-free days in zone 4b. The last frost comes by May 10 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 1.
Months with highs of 62–84° and lows of 40° or more: June, July and August. 6.2 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Iliamna from natural hazards, earthquakes are the largest share (46%); heat waves, cold waves, winter storms and ice storms together are 16%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Iliamna and similar climates
TownRatings has no climate map of the towns around Iliamna yet.
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
How Iliamna compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Iliamna’s place among Alaska’s.
Iliamna weather by month
Highs, lows and precipitation from the nearest NOAA station. 1991–2020 normals.
| Month | High | Low | Rain + melt |
|---|---|---|---|
| January | 25° | 12° | 0.9" |
| February | 30° | 16° | 1.1" |
| March | 32° | 16° | 0.8" |
| April | 43° | 29° | 0.8" |
| May | 55° | 38° | 1.2" |
| June | 62° | 45° | 1.5" |
| July | 65° | 51° | 3.1" |
| August | 64° | 50° | 4.1" |
| September | 56° | 43° | 5.0" |
| October | 45° | 32° | 2.8" |
| November | 33° | 21° | 2.2" |
| December | 28° | 15° | 1.5" |
| Year | 45° | 31° | 25.0" |
Where Iliamna’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: Iliamna Airport, 5 miles from the town’s center, 200 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 Iliamna’s climate
What is the weather like in Iliamna?
A typical July afternoon reaches 65°, a January night drops to 12°. Colder January nights than 91% of U.S. towns; cooler July afternoons than all but 21 U.S. towns.
How cold does it get in Iliamna in winter?
January nights average 12°. About 170 nights a year reach 32° or below and 32 reach 0° or below.
How hot does it get in Iliamna?
July, with a typical high of 65°. 90° days are rare: none in a normal year at Iliamna Airport.
When is the first and last frost in Iliamna?
In half of years the last spring frost (32°) comes by May 10 and the first fall frost by October 1, about 144 frost-free days, at Iliamna Airport.
What growing zone is Iliamna in?
Zone 4b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −22°.
What is the best time of year to visit Iliamna?
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 Iliamna.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.