Dutch Harbor, Alaska climate: Climate normals at a NOAA weather station
Dutch Harbor's normal year runs from 29°F January nights to 59°F August afternoons, with 60.1 inches of precipitation and 82 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.3°C, January lows of −2°C, August highs of 15°C, 1,527 mm of precipitation a year.
- NOAA stationDutch Harbor
- Station IDUSC00502587
- Location53.90°N 166.54°W
- Elevation10 ft (3 m)
On October 23, the normal high in Dutch Harbor is 47°F and the normal low 37°F, and the chance of measurable rain or snow is 80%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Dutch Harbor.
- Jan 37° 29°
- Feb 39° 29°
- Mar 39° 29°
- Apr 42° 33°
- May 47° 37°
- Jun 52° 42°
- Jul 57° 47°
- Aug 59° 48°
- Sep 55° 44°
- Oct 48° 38°
- Nov 43° 33°
- Dec 39° 31°
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 Dutch Harbor each month?
August is the warmest month, with normal highs of 59°F; January the coldest, with normal lows of 29°F. The most precipitation falls in October (7.89 in), the least in July (2.30 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 37°F | 29°F | 33.0°F | 6.79 | 22.0 | 22 | <1 | 21 | 8 h |
| February | 39°F | 29°F | 34.0°F | 5.18 | 14.2 | 19 | <1 | 18 | 9 h 50 min |
| March | 39°F | 29°F | 34.1°F | 4.65 | 16.5 | 19 | <1 | 22 | 11 h 40 min |
| April | 42°F | 33°F | 37.1°F | 3.47 | 6.3 | 18 | <1 | 14 | 14 h |
| May | 47°F | 37°F | 42.0°F | 4.20 | 0.2 | 18 | <1 | 3 | 15 h 50 min |
| June | 52°F | 42°F | 47.3°F | 2.52 | 0.0 | 15 | <1 | <1 | 17 h |
| July | 57°F | 47°F | 52.0°F | 2.30 | 0.0 | 14 | <1 | <1 | 16 h 40 min |
| August | 59°F | 48°F | 53.7°F | 2.86 | 0.0 | 15 | <1 | <1 | 15 h |
| September | 55°F | 44°F | 49.4°F | 5.73 | 0.0 | 20 | <1 | 1 | 12 h 50 min |
| October | 48°F | 38°F | 43.2°F | 7.89 | 0.4 | 25 | <1 | 4 | 10 h 40 min |
| November | 43°F | 33°F | 38.2°F | 6.66 | 6.2 | 23 | <1 | 12 | 8 h 40 min |
| December | 39°F | 31°F | 35.0°F | 7.88 | 15.8 | 23 | <1 | 19 | 7 h 30 min |
| Year (annual) | 47°F | 37°F | 41.6°F | 60.13 | 81.6 | 231 | <1 | 112 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −2°C | 0.6°C | 172 mm | 56 cm |
| February | 4°C | −1°C | 1.1°C | 132 mm | 36 cm |
| March | 4°C | −2°C | 1.2°C | 118 mm | 42 cm |
| April | 5°C | 0°C | 2.8°C | 88 mm | 16 cm |
| May | 8°C | 3°C | 5.6°C | 107 mm | 1 cm |
| June | 11°C | 6°C | 8.5°C | 64 mm | 0 cm |
| July | 14°C | 8°C | 11.1°C | 58 mm | 0 cm |
| August | 15°C | 9°C | 12.1°C | 73 mm | 0 cm |
| September | 13°C | 7°C | 9.7°C | 146 mm | 0 cm |
| October | 9°C | 4°C | 6.2°C | 200 mm | 1 cm |
| November | 6°C | 1°C | 3.4°C | 169 mm | 16 cm |
| December | 4°C | −1°C | 1.7°C | 200 mm | 40 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00502587; 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 Dutch Harbor?
No month's normal high reaches 65°F in Dutch Harbor: the warmest is August at 59°F.
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 USC00502587.
When is the last frost at Dutch Harbor?
In Dutch Harbor, the last spring frost (32°F) comes after May 6 in half of years and after May 22 in one year in ten; the first autumn frost comes before October 18 in half of years and before September 20 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 61 year in 10 after May 22; 9 in 10 after April 23
- First autumn frost, half of years before
- October 181 year in 10 before September 20; 9 in 10 before November 5
NOAA puts the median frost-free season at 164 days, and the season without a hard freeze (28°F) at 198 days.
A hard freeze (28°F) comes after April 19 in half of springs and before November 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Dutch Harbor in zone 8b in ZIP code 99692, 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 8a: the coldest night of a typical year reaches 14°F (20 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 USC00502587; 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 Dutch Harbor?
In a normal year in Dutch Harbor, a 90°F day is rare, 112 nights fall to 32°F or colder and 231 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
- 112a normal year
- Days that stay below freezing
- 17high of 32°F or less
- Days with 0.01 inch of precipitation
- 231a normal year
- Days with 1 inch of snow or more
- 36a normal year
The highest temperature in this station's record (since 1915) is 82°F, on August 28, 1982; the lowest is 0°F, on February 5, 1991.
The wettest calendar year on that record is 2003, with 85.62 in; the snowiest season is 1998–99, with 174.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00502587; records: ACIS (NOAA Regional Climate Centers), station USC00502587. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Dutch Harbor?
Over a year 54% of the sunlight that would reach the ground under clear skies gets through the clouds at Dutch Harbor, 2.4 kWh per square metre a day. October is the sunniest month (56%) and December the cloudiest (48%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 49% | 0.6 |
| February | 50% | 1.2 |
| March | 56% | 2.4 |
| April | 56% | 3.5 |
| May | 56% | 4.2 |
| June | 54% | 4.5 |
| July | 52% | 4.0 |
| August | 54% | 3.4 |
| September | 55% | 2.6 |
| October | 56% | 1.6 |
| November | 52% | 0.8 |
| December | 48% | 0.4 |
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 Dutch Harbor record?
A normal year at Dutch Harbor brings 8,526 heating degree days, 59% more than the median U.S. place (5,373), and 1 cooling degree days, 100% fewer than the median (908). Twelve months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 250 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 992 | 0 |
| February | 868 | 0 |
| March | 959 | 0 |
| April | 836 | 0 |
| May | 712 | 0 |
| June | 530 | 0 |
| July | 403 | 0 |
| August | 351 | 1 |
| September | 468 | 0 |
| October | 674 | 0 |
| November | 803 | 0 |
| December | 932 | 0 |
| Year (annual) | 8,526 | 1 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00502587. 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 Dutch Harbor been warmer than normal?
2025 averaged 43.1°F, 1.5°F above the 1991-2020 normal of 41.6°F.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2025 | 43.1°F | +1.5°F | – | 52.9 |
Over 56 complete years from 1882 to 2022, the station's annual mean temperature rose at a fitted 4.0°F per century (+0.22°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00502587; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Dutch Harbor's climate compare?
Dutch Harbor is warmer than 67 of the 85 places with their own NOAA record in Alaska, and wetter than 54. Across the 7,247 U.S. stations with normals, its annual mean of 41.6°F is warmer than 9%.
In the Köppen classification computed from these normals, Dutch Harbor is Cfc: temperate, 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.
Which places near Dutch Harbor share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Unalaska, AK4,407 people · 1 mi NE
- Akutan, AK1,596 people · 36 mi NE
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Dutch Harbor's climate
What is the coldest month at Dutch Harbor?
January, with a normal high of 37°F and a normal low of 29°F. The warmest is August (59°F by day, 48°F at night).
Does it snow at Dutch Harbor?
Yes: 82 inches in a normal year, falling on 45 days with 0.1 inch or more, the most in January (22.0 inches).
What is the rainiest month at Dutch Harbor?
October, with 7.89 in of precipitation in a normal year; the driest is July with 2.30 in.
What plant hardiness zone is Dutch Harbor in?
The USDA's 2023 map puts Dutch Harbor in zone 8b in ZIP code 99692, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 14°F (20 years, 1991-2020): zone 8a.
How late can frost come at Dutch Harbor?
In half of years the last 32°F night comes after May 6; 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
- Cold Bay, AK178 miles from this station, 39.3°F a year
- St. George, AK222 miles from this station, 36.7°F a year
- Sand Point, AK263 miles from this station, 39.9°F a year
- St. Paul, AK267 miles from this station, 35.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made