Alyeska, Alaska climate: Climate normals at a NOAA weather station
Alyeska's normal year runs from 17°F January nights to 67°F July afternoons, with 70.9 inches of precipitation and 215 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 3.7°C, January lows of −8°C, July highs of 19°C, 1,801 mm of precipitation a year.
- NOAA stationAlyeska
- Station IDUSC00500243
- Location60.96°N 149.11°W
- Elevation272 ft (83 m)
On October 23, the normal high in Alyeska is 41°F and the normal low 29°F, and the chance of measurable rain or snow is 59%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Alyeska.
- Jan 27° 17°
- Feb 31° 19°
- Mar 36° 20°
- Apr 46° 29°
- May 55° 37°
- Jun 64° 45°
- Jul 67° 50°
- Aug 65° 48°
- Sep 56° 41°
- Oct 44° 32°
- Nov 33° 22°
- Dec 29° 19°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Alyeska each month?
July is the warmest month, with normal highs of 67°F; January the coldest, with normal lows of 17°F. The most precipitation falls in December (8.98 in), the least in June (2.21 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 27°F | 17°F | 22.0°F | 7.34 | 37.4 | 19 | <1 | 27 | 6 h 20 min |
| February | 31°F | 19°F | 25.4°F | 6.57 | 36.6 | 18 | <1 | 24 | 9 h |
| March | 36°F | 20°F | 27.6°F | 5.37 | 37.5 | 16 | <1 | 28 | 11 h 40 min |
| April | 46°F | 29°F | 37.1°F | 5.25 | 9.6 | 16 | <1 | 21 | 14 h 30 min |
| May | 55°F | 37°F | 46.2°F | 3.99 | 1.2 | 14 | <1 | 5 | 17 h 20 min |
| June | 64°F | 45°F | 54.2°F | 2.21 | 0.0 | 12 | <1 | <1 | 19 h 10 min |
| July | 67°F | 50°F | 58.1°F | 2.66 | 0.0 | 14 | <1 | <1 | 18 h 30 min |
| August | 65°F | 48°F | 56.0°F | 4.86 | 0.0 | 17 | <1 | <1 | 15 h 50 min |
| September | 56°F | 41°F | 48.5°F | 8.26 | 0.0 | 20 | <1 | 3 | 13 h |
| October | 44°F | 32°F | 38.0°F | 7.78 | 8.1 | 19 | <1 | 16 | 10 h 10 min |
| November | 33°F | 22°F | 27.4°F | 7.65 | 29.9 | 18 | <1 | 24 | 7 h 30 min |
| December | 29°F | 19°F | 24.3°F | 8.98 | 54.2 | 22 | <1 | 27 | 5 h 40 min |
| Year (annual) | 46°F | 31°F | 38.7°F | 70.92 | 214.5 | 204 | <1 | 175 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −8°C | −5.6°C | 186 mm | 95 cm |
| February | 0°C | −7°C | −3.7°C | 167 mm | 93 cm |
| March | 2°C | −7°C | −2.4°C | 136 mm | 95 cm |
| April | 8°C | −2°C | 2.8°C | 133 mm | 24 cm |
| May | 13°C | 3°C | 7.9°C | 101 mm | 3 cm |
| June | 18°C | 7°C | 12.3°C | 56 mm | 0 cm |
| July | 19°C | 10°C | 14.5°C | 68 mm | 0 cm |
| August | 18°C | 9°C | 13.3°C | 123 mm | 0 cm |
| September | 13°C | 5°C | 9.2°C | 210 mm | 0 cm |
| October | 7°C | 0°C | 3.3°C | 198 mm | 21 cm |
| November | 0°C | −5°C | −2.6°C | 194 mm | 76 cm |
| December | −1°C | −7°C | −4.3°C | 228 mm | 138 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00500243; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Alyeska?
Normal highs sit between 65°F and 85°F in July.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00500243.
When is the last frost at Alyeska?
In Alyeska, the last spring frost (32°F) comes after May 8 in half of years and after May 22 in one year in ten; the first autumn frost comes before September 29 in half of years and before September 14 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 81 year in 10 after May 22; 9 in 10 after April 26
- First autumn frost, half of years before
- September 291 year in 10 before September 14; 9 in 10 before October 13
NOAA puts the median frost-free season at 142 days, and the season without a hard freeze (28°F) at 169 days.
A hard freeze (28°F) comes after April 26 in half of springs and before October 11 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Alyeska in zone 5b in ZIP code 99540, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 6a: the coldest night of a typical year reaches −8°F (30 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Alaska · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00500243; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Alyeska?
In a normal year in Alyeska, a 90°F day is rare, 175 nights fall to 32°F or colder and 204 days bring measurable precipitation.
- Days at 90°F or more
- fewer than 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 175a normal year
- Days that stay below freezing
- 71high of 32°F or less
- Days with 0.01 inch of precipitation
- 204a normal year
- Days with 1 inch of snow or more
- 52a normal year
The highest temperature in this station's record (since 1963) is 89°F, on July 9, 2019; the lowest is −30°F, on January 29, 1989.
The wettest calendar year on that record is 2001, with 95.32 in; the snowiest season is 1999–00, with 375.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00500243; records: ACIS (NOAA Regional Climate Centers), station USC00500243. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Alyeska?
Over a year 59% of the sunlight that would reach the ground under clear skies gets through the clouds at Alyeska, 2.4 kWh per square metre a day. March is the sunniest month (64%) and November the cloudiest (52%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 53% | 0.3 |
| February | 55% | 0.9 |
| March | 64% | 2.3 |
| April | 61% | 3.6 |
| May | 61% | 4.6 |
| June | 59% | 4.9 |
| July | 60% | 4.6 |
| August | 58% | 3.5 |
| September | 57% | 2.3 |
| October | 53% | 1.1 |
| November | 52% | 0.4 |
| December | 53% | 0.2 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Alyeska record?
A normal year at Alyeska brings 9,565 heating degree days, 78% more than the median U.S. place (5,373), and 6 cooling degree days, 99% fewer than the median (908). Ten months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 643 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,335 | 0 |
| February | 1,110 | 0 |
| March | 1,159 | 0 |
| April | 837 | 0 |
| May | 583 | 0 |
| June | 324 | 1 |
| July | 219 | 3 |
| August | 279 | 1 |
| September | 494 | 0 |
| October | 839 | 0 |
| November | 1,126 | 0 |
| December | 1,262 | 0 |
| Year (annual) | 9,565 | 6 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00500243. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Alyeska been warmer than normal?
2024 averaged 38.9°F, 0.2°F above the 1991-2020 normal of 38.7°F. 2 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 36.8°F | −1.9°F | 71.75 | 193.8 |
| 2022 | 39.8°F | +1.1°F | 67.25 | 188.5 |
| 2023 | 38.7°F | at normal | 67.68 | 265.2 |
| 2024 | 38.9°F | +0.2°F | 65.21 | 130.3 |
Over 34 complete years from 1984 to 2024, the station's annual mean temperature rose at a fitted 6.1°F per century (+0.34°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00500243; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Alyeska's climate compare?
Alyeska is warmer than 56 of the 85 places with their own NOAA record in Alaska, and wetter than 58. Across the 7,247 U.S. stations with normals, its annual mean of 38.7°F is warmer than 4%.
In the Köppen classification computed from these normals, Alyeska is Dfc: continental, no dry season, cool summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Questions about Alyeska's climate
What is the coldest month at Alyeska?
January, with a normal high of 27°F and a normal low of 17°F. The warmest is July (67°F by day, 50°F at night).
Does it snow at Alyeska?
Yes: 215 inches in a normal year, falling on 62 days with 0.1 inch or more, the most in December (54.2 inches).
What is the rainiest month at Alyeska?
December, with 8.98 in of precipitation in a normal year; the driest is June with 2.21 in.
What plant hardiness zone is Alyeska in?
The USDA's 2023 map puts Alyeska in zone 5b in ZIP code 99540, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −8°F (30 years, 1991-2020): zone 6a.
How late can frost come at Alyeska?
In half of years the last 32°F night comes after May 8; in one year in ten it comes after May 22. Waiting until May 22 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Alaska climateThe statewide normals and every place in the state
- Portage Glacier V C, AK15 miles from this station, 37.1°F a year
- Hope, AK18 miles from this station, 36.5°F a year
- Whittier, AK19 miles from this station, 41.1°F a year
- Eagle River Nature Center, AK20 miles from this station, 35.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made