Willow, Alaska climate: Normal weather by month, frost dates and records
Willow's normal year runs from −4°F January nights to 68°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 0.8°C, January lows of −20°C, July highs of 20°C.
- NOAA stationWillow West
- Station IDUSC00509861
- Location61.75°N 150.05°W
- Elevation205 ft (63 m)
- From the center17 miles
- Population (census place)1,769
On October 14, the normal high in Willow is 42°F and the normal low 26°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Willow.
- Jan 15° -4°
- Feb 25° 2°
- Mar 34° 7°
- Apr 46° 25°
- May 58° 37°
- Jun 67° 47°
- Jul 68° 52°
- Aug 65° 49°
- Sep 56° 39°
- Oct 41° 24°
- Nov 24° 7°
- Dec 18° 0°
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 Willow each month?
July is the warmest month, with normal highs of 68°F; January the coldest, with normal lows of −4°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 15°F | −4°F | 5.7°F | – | <1 | 31 | 6 h 10 min |
| February | 25°F | 2°F | 13.4°F | – | <1 | 28 | 8 h 50 min |
| March | 34°F | 7°F | 20.9°F | – | <1 | 31 | 11 h 40 min |
| April | 46°F | 25°F | 35.5°F | – | <1 | 26 | 14 h 40 min |
| May | 58°F | 37°F | 47.6°F | – | <1 | 10 | 17 h 30 min |
| June | 67°F | 47°F | 56.7°F | – | <1 | <1 | 19 h 40 min |
| July | 68°F | 52°F | 60.1°F | – | <1 | <1 | 18 h 50 min |
| August | 65°F | 49°F | 56.8°F | – | <1 | <1 | 16 h |
| September | 56°F | 39°F | 47.4°F | – | <1 | 7 | 13 h |
| October | 41°F | 24°F | 32.3°F | – | <1 | 27 | 10 h 10 min |
| November | 24°F | 7°F | 15.5°F | – | <1 | 29 | 7 h 10 min |
| December | 18°F | 0°F | 8.8°F | – | <1 | 31 | 5 h 20 min |
| Year (annual) | 43°F | 24°F | 33.4°F | – | <1 | 219 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | −9°C | −20°C | −14.6°C |
| February | −4°C | −17°C | −10.3°C |
| March | 1°C | −14°C | −6.2°C |
| April | 8°C | −4°C | 1.9°C |
| May | 15°C | 3°C | 8.7°C |
| June | 19°C | 8°C | 13.7°C |
| July | 20°C | 11°C | 15.6°C |
| August | 18°C | 9°C | 13.8°C |
| September | 13°C | 4°C | 8.6°C |
| October | 5°C | −4°C | 0.2°C |
| November | −5°C | −14°C | −9.2°C |
| December | −8°C | −18°C | −12.9°C |
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 USC00509861; 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 Willow?
Normal highs sit between 65°F and 85°F in June, July and August.
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 USC00509861.
When is the last frost in Willow?
In Willow, the last spring frost (32°F) comes after May 15 in half of years and after May 28 in one year in ten; the first autumn frost comes before September 18 in half of years and before September 4 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 151 year in 10 after May 28; 9 in 10 after May 3
- First autumn frost, half of years before
- September 181 year in 10 before September 4; 9 in 10 before September 28
NOAA puts the median frost-free season at 126 days, and the season without a hard freeze (28°F) at 146 days.
A hard freeze (28°F) comes after May 3 in half of springs and before September 27 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Willow in zones 3b to 4a across its 2 ZIP code areas (3b in 99688, the largest).
Frost dates for every NOAA station in Alaska · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00509861; 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.
What hardiness zone is each Willow ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Willow's 2 ZIP code areas run from zone 3b to 4a: 1 in 3b and 1 in 4a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Willow?
In a normal year in Willow, a 90°F day is rare and 219 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
- 219a normal year
- Days that stay below freezing
- 117high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00509861.
How sunny is Willow?
Over a year 66% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Willow, 2.5 kWh per square metre a day. March is the sunniest month (74%) and December the cloudiest (56%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 60% | 0.3 |
| February | 62% | 0.9 |
| March | 74% | 2.6 |
| April | 74% | 4.1 |
| May | 67% | 4.8 |
| June | 67% | 5.4 |
| July | 64% | 4.8 |
| August | 64% | 3.7 |
| September | 61% | 2.4 |
| October | 58% | 1.1 |
| November | 59% | 0.4 |
| December | 56% | 0.1 |
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 Willow need?
A normal year in Willow brings 11,521 heating degree days, 2.1 times the median U.S. place (5,373), and 19 cooling degree days, 98% fewer than the median (908). Nine months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 808 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,838 | 0 |
| February | 1,446 | 0 |
| March | 1,369 | 0 |
| April | 885 | 0 |
| May | 540 | 0 |
| June | 254 | 6 |
| July | 162 | 10 |
| August | 257 | 3 |
| September | 528 | 0 |
| October | 1,014 | 0 |
| November | 1,486 | 0 |
| December | 1,742 | 0 |
| Year (annual) | 11,521 | 19 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00509861. 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.
How does Willow's climate compare?
Willow is warmer than 38 of the other 84 places with their own NOAA record in Alaska. Across the 7,247 U.S. stations with normals, its annual mean of 33.4°F is warmer than 1%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Questions about Willow's climate
What is the coldest month in Willow?
January, with a normal high of 15°F and a normal low of −4°F. The warmest is July (68°F by day, 52°F at night).
What plant hardiness zone is Willow in?
The USDA's 2023 map puts Willow in zones 3b to 4a across its 2 ZIP code areas (3b in 99688, the largest).
How late can frost come in Willow?
In half of years the last 32°F night comes after May 15; in one year in ten it comes after May 28. Waiting until May 28 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Alaska climateThe statewide normals and every place in the state
- Whites Crossing, AK3 miles from this station, 33.4°F a year
- North Lakes, AK25 miles from this station, 37.0°F a year
- Little Su At Hatcher Pass Bridge, AK27 miles from this station, 35.6°F a year
- Matanuska Experiment Farm, AK29 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