Sterling, Alaska climate: Normal weather by month, frost dates and records
Sterling's normal year runs from 8°F January nights to 66°F July afternoons, with 23.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 2.1°C, January lows of −13°C, July highs of 19°C, 586 mm of precipitation a year.
- NOAA stationSterling (6 mi SW)
- Station IDUSC00508731
- Location60.49°N 150.92°W
- Elevation292 ft (89 m)
- Population (census place)6,776
On October 23, the normal high in Sterling is 38°F and the normal low 24°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sterling.
- Jan 22° 8°
- Feb 28° 12°
- Mar 33° 15°
- Apr 46° 28°
- May 56° 35°
- Jun 63° 44°
- Jul 66° 49°
- Aug 64° 47°
- Sep 55° 40°
- Oct 42° 28°
- Nov 28° 15°
- Dec 23° 10°
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 Sterling each month?
July is the warmest month, with normal highs of 66°F; January the coldest, with normal lows of 8°F. The most precipitation falls in September (3.45 in), the least in March (0.91 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 22°F | 8°F | 14.9°F | 1.32 | – | <1 | 30 | 6 h 30 min |
| February | 28°F | 12°F | 19.9°F | 1.81 | – | <1 | 28 | 9 h |
| March | 33°F | 15°F | 23.9°F | 0.91 | – | <1 | 30 | 11 h 40 min |
| April | 46°F | 28°F | 36.8°F | 0.94 | – | <1 | 22 | 14 h 30 min |
| May | 56°F | 35°F | 45.9°F | 0.96 | – | <1 | 8 | 17 h 10 min |
| June | 63°F | 44°F | 53.5°F | 1.68 | – | <1 | 1 | 19 h |
| July | 66°F | 49°F | 57.6°F | 2.44 | – | <1 | <1 | 18 h 20 min |
| August | 64°F | 47°F | 55.6°F | 3.22 | – | <1 | <1 | 15 h 50 min |
| September | 55°F | 40°F | 47.2°F | 3.45 | – | <1 | 5 | 13 h |
| October | 42°F | 28°F | 34.7°F | 2.77 | – | <1 | 19 | 10 h 20 min |
| November | 28°F | 15°F | 21.8°F | 1.78 | – | <1 | 28 | 7 h 30 min |
| December | 23°F | 10°F | 16.8°F | 1.78 | – | <1 | 30 | 5 h 50 min |
| Year (annual) | 44°F | 28°F | 35.7°F | 23.06 | – | <1 | 200 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −6°C | −13°C | −9.5°C | 34 mm |
| February | −2°C | −11°C | −6.7°C | 46 mm |
| March | 1°C | −10°C | −4.5°C | 23 mm |
| April | 8°C | −2°C | 2.7°C | 24 mm |
| May | 14°C | 2°C | 7.7°C | 24 mm |
| June | 17°C | 6°C | 11.9°C | 43 mm |
| July | 19°C | 9°C | 14.2°C | 62 mm |
| August | 18°C | 9°C | 13.1°C | 82 mm |
| September | 13°C | 4°C | 8.4°C | 88 mm |
| October | 5°C | −2°C | 1.5°C | 70 mm |
| November | −2°C | −9°C | −5.7°C | 45 mm |
| December | −5°C | −12°C | −8.4°C | 45 mm |
NOAA publishes no 1991-2020 snowfall normal for this station, and no record within 25 miles keeps one, so snow is left out here rather than estimated.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00508731; 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 Sterling?
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 USC00508731.
When is the last frost in Sterling?
In Sterling, the last spring frost (32°F) comes after May 20 in half of years and after June 1 in one year in ten; the first autumn frost comes before September 21 in half of years and before September 6 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 201 year in 10 after June 1; 9 in 10 after May 6
- First autumn frost, half of years before
- September 211 year in 10 before September 6; 9 in 10 before October 4
NOAA puts the median frost-free season at 123 days, and the season without a hard freeze (28°F) at 148 days.
A hard freeze (28°F) comes after May 3 in half of springs and before September 30 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sterling in zone 4b in ZIP code 99672.
Frost dates for every NOAA station in Alaska · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00508731; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Sterling?
In a normal year in Sterling, a 90°F day is rare and 200 nights fall to 32°F or colder.
- 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
- 200a normal year
- Days that stay below freezing
- 103high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00508731.
How sunny is Sterling?
Over a year 66% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Sterling, 2.6 kWh per square metre a day. March is the sunniest month (70%) and December the cloudiest (55%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 60% | 0.3 |
| February | 62% | 1.0 |
| March | 70% | 2.4 |
| April | 68% | 3.8 |
| May | 68% | 5.0 |
| June | 68% | 5.5 |
| July | 65% | 4.8 |
| August | 65% | 3.8 |
| September | 62% | 2.4 |
| October | 59% | 1.2 |
| November | 60% | 0.4 |
| December | 55% | 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 Sterling need?
A normal year in Sterling brings 10,671 heating degree days, 99% more than the median U.S. place (5,373), and 7 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 570 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,553 | 0 |
| February | 1,263 | 0 |
| March | 1,274 | 0 |
| April | 846 | 0 |
| May | 592 | 0 |
| June | 348 | 2 |
| July | 234 | 3 |
| August | 294 | 2 |
| September | 536 | 0 |
| October | 939 | 0 |
| November | 1,298 | 0 |
| December | 1,494 | 0 |
| Year (annual) | 10,671 | 7 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00508731. 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 Sterling been warmer than normal lately?
2025 averaged 39.5°F, 3.8°F above the 1991-2020 normal of 35.7°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 34.3°F | −1.4°F | 21.32 |
| 2022 | 37.6°F | +1.9°F | 28.02 |
| 2023 | 36.4°F | +0.7°F | 23.27 |
| 2025 | 39.5°F | +3.8°F | 22.38 |
Source: observed years: ACIS, station USC00508731. A year counts only with all twelve months complete.
How does Sterling's climate compare?
Sterling is warmer than 44 of the other 84 places with their own NOAA record in Alaska, and wetter than 41. Across the 7,247 U.S. stations with normals, its annual mean of 35.7°F is warmer than 2%.
In the Köppen classification computed from these normals, Sterling 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 Sterling 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.
- Ridgeway, AK2,174 people · 5 mi NW
- Funny River, AK1,127 people · 4 mi E
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 Sterling's climate
What is the coldest month in Sterling?
January, with a normal high of 22°F and a normal low of 8°F. The warmest is July (66°F by day, 49°F at night).
What is the rainiest month in Sterling?
September, with 3.45 in of precipitation in a normal year; the driest is March with 0.91 in.
What plant hardiness zone is Sterling in?
The USDA's 2023 map puts Sterling in zone 4b in ZIP code 99672.
How late can frost come in Sterling?
In half of years the last 32°F night comes after May 20; in one year in ten it comes after June 1. Waiting until June 1 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Alaska climateThe statewide normals and every place in the state
- Soldotna, AK9 miles from this station, 34.1°F a year
- Kenai, AK12 miles from this station, 35.6°F a year
- Kenai (29 mi ENE), AK22 miles from this station, 34.2°F a year
- Cooper Landing, AK32 miles from this station, 36.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made