Seward, Alaska climate: Normal weather by month, frost dates and records
Seward's normal year runs from 21°F January nights to 62°F July afternoons, with 69.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 4.7°C, January lows of −6°C, July highs of 17°C, 1,771 mm of precipitation a year.
- NOAA stationSeward Airport
- Station IDUSW00026438
- Location60.13°N 149.42°W
- Elevation22 ft (7 m)
- Population2,882
On October 23, the normal high in Seward is 43°F and the normal low 33°F, and the chance of measurable rain or snow is 51%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Seward.
- Jan 31° 21°
- Feb 34° 24°
- Mar 37° 25°
- Apr 45° 32°
- May 53° 39°
- Jun 59° 46°
- Jul 62° 50°
- Aug 62° 50°
- Sep 56° 43°
- Oct 46° 35°
- Nov 36° 27°
- Dec 33° 23°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Seward each month?
July is the warmest month, with normal highs of 62°F; January the coldest, with normal lows of 21°F. The most precipitation falls in September (9.90 in), the least in June (2.34 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 31°F | 21°F | 26.2°F | 6.47 | 14 | <1 | 25 | 6 h 40 min |
| February | 34°F | 24°F | 28.9°F | 6.35 | 14 | <1 | 22 | 9 h 10 min |
| March | 37°F | 25°F | 31.1°F | 3.85 | 12 | <1 | 25 | 11 h 40 min |
| April | 45°F | 32°F | 38.8°F | 4.29 | 14 | <1 | 13 | 14 h 30 min |
| May | 53°F | 39°F | 46.3°F | 3.50 | 14 | <1 | 2 | 17 h 10 min |
| June | 59°F | 46°F | 52.3°F | 2.34 | 11 | <1 | <1 | 18 h 50 min |
| July | 62°F | 50°F | 56.2°F | 3.11 | 13 | <1 | <1 | 18 h 10 min |
| August | 62°F | 50°F | 55.8°F | 5.39 | 15 | <1 | <1 | 15 h 50 min |
| September | 56°F | 43°F | 49.6°F | 9.90 | 17 | <1 | 1 | 13 h |
| October | 46°F | 35°F | 40.2°F | 8.69 | 17 | <1 | 10 | 10 h 20 min |
| November | 36°F | 27°F | 31.4°F | 7.60 | 14 | <1 | 22 | 7 h 40 min |
| December | 33°F | 23°F | 28.2°F | 8.22 | 16 | <1 | 26 | 5 h 50 min |
| Year (annual) | 46°F | 35°F | 40.4°F | 69.71 | 171 | <1 | 146 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 0°C | −6°C | −3.2°C | 164 mm |
| February | 1°C | −5°C | −1.7°C | 161 mm |
| March | 3°C | −4°C | −0.5°C | 98 mm |
| April | 7°C | 0°C | 3.8°C | 109 mm |
| May | 12°C | 4°C | 7.9°C | 89 mm |
| June | 15°C | 8°C | 11.3°C | 59 mm |
| July | 17°C | 10°C | 13.4°C | 79 mm |
| August | 17°C | 10°C | 13.2°C | 137 mm |
| September | 13°C | 6°C | 9.8°C | 251 mm |
| October | 8°C | 2°C | 4.6°C | 221 mm |
| November | 2°C | −3°C | −0.3°C | 193 mm |
| December | 1°C | −5°C | −2.1°C | 209 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. Seward's own co-op station Seward (19 mi N) does: 90 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USW00026438; 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.
When is the best weather to visit Seward?
No month's normal high reaches 65°F in Seward: the warmest is July at 62°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 USW00026438.
When is the last frost in Seward?
In Seward, the last spring frost (32°F) comes after May 2 in half of years and after May 17 in one year in ten; the first autumn frost comes before October 7 in half of years and before September 28 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 21 year in 10 after May 17; 9 in 10 after April 20
- First autumn frost, half of years before
- October 71 year in 10 before September 28; 9 in 10 before October 23
NOAA puts the median frost-free season at 158 days, and the season without a hard freeze (28°F) at 187 days.
A hard freeze (28°F) comes after April 15 in half of springs and before October 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Seward in zone 5b in ZIP code 99664, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Seward's NOAA station is in zone 7a: the coldest night of a typical year reaches 1°F (28 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 USW00026438; 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 in Seward?
In a normal year in Seward, a 90°F day is rare, 146 nights fall to 32°F or colder and 171 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
- 146a normal year
- Days that stay below freezing
- 49high of 32°F or less
- Days with 0.01 inch of precipitation
- 171a normal year
The highest temperature in this station's record (since 1908) is 95°F, on August 12, 1966; the lowest is −20°F, on January 29, 1919.
The wettest calendar year on that record is 1981, with 96.37 in; the snowiest season is 1998–99, with 184.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00026438; records: ACIS (NOAA Regional Climate Centers), station USW00026438. Records use complete months only; a month missing more than three days is left out.
How sunny is Seward?
Over a year 59% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Seward, 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 much heating and cooling does Seward need?
A normal year in Seward brings 8,960 heating degree days, 67% more than the median U.S. place (5,373), and 9 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 539 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,203 | 0 |
| February | 1,011 | 0 |
| March | 1,051 | 0 |
| April | 786 | 0 |
| May | 580 | 0 |
| June | 381 | 2 |
| July | 278 | 5 |
| August | 288 | 2 |
| September | 464 | 0 |
| October | 769 | 0 |
| November | 1,009 | 0 |
| December | 1,141 | 0 |
| Year (annual) | 8,960 | 9 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00026438. 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.
Has Seward been warmer than normal lately?
2024 averaged 38.9°F, 1.5°F below the 1991-2020 normal of 40.4°F. 1 of the 3 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 41.1°F | +0.7°F | – |
| 2023 | 39.7°F | −0.7°F | 54.56 |
| 2024 | 38.9°F | −1.5°F | 56.76 |
Over 78 complete years from 1910 to 2024, the station's annual mean temperature rose at a fitted 1.6°F per century (+0.09°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00026438; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Seward's climate compare?
Seward is warmer than 62 of the other 84 places with their own NOAA record in Alaska, and wetter than 57. Across the 7,247 U.S. stations with normals, its annual mean of 40.4°F is warmer than 6%.
In the Köppen classification computed from these normals, Seward 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.
Which places near Seward 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.
- Bear Creek, AK1,360 people · 6 mi N
- Lowell Point, AK0 people · 4 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Seward's other NOAA stations record?
2 more NOAA stations keep 1991-2020 normals in or near Seward. This page uses Seward Airport; the others differ by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Seward (19 mi N) USC00508377 | 16 mi N | 518 ft | 37.2°F | 16°F | 64°F | 45.5 | 90 | May 21 |
| Seward (8 mi NW) USC00508375 | 8 mi NW | 424 ft | 35.3°F | 7°F | 67°F | – | – | – |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Seward's climate
What is the coldest month in Seward?
January, with a normal high of 31°F and a normal low of 21°F. The warmest is July (62°F by day, 50°F at night).
Does it snow in Seward?
Yes. NOAA publishes no 1991-2020 snowfall normal for Seward's NOAA station; Seward's own co-op station Seward (19 mi N) records 90 inches of snow in a normal year.
What is the rainiest month in Seward?
September, with 9.90 in of precipitation in a normal year; the driest is June with 2.34 in.
What plant hardiness zone is Seward in?
The USDA's 2023 map puts Seward in zone 5b in ZIP code 99664, the nearest ZIP area. By the same method at Seward's NOAA station, the coldest night of a typical year reaches 1°F (28 years, 1991-2020): zone 7a.
How late can frost come in Seward?
In half of years the last 32°F night comes after May 2; in one year in ten it comes after May 17. Waiting until May 17 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Alaska climateThe statewide normals and every place in the state
- Cooper Lake Project, AK20 miles from this station, 38.4°F a year
- Moose Pass, AK26 miles from this station, 35.7°F a year
- Cooper Landing, AK31 miles from this station, 36.7°F a year
- Port San Juan, AK47 miles from this station, 40.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made