Port Alexander, Alaska climate: Normal weather by month, frost dates and records
Port Alexander's normal year runs from 32°F January nights to 64°F July afternoons, with 162.0 inches of precipitation and 56 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.6°C, January lows of 0°C, July highs of 18°C, 4,116 mm of precipitation a year.
- NOAA stationPort Alexander
- Station IDUSC00507557
- Location56.25°N 134.64°W
- Elevation12 ft (4 m)
- From the centerunder 1 mile
- Population74
On October 23, the normal high in Port Alexander is 49°F and the normal low 40°F, and the chance of measurable rain or snow is 82%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Port Alexander.
- Jan 40° 32°
- Feb 41° 33°
- Mar 43° 33°
- Apr 50° 37°
- May 57° 42°
- Jun 61° 47°
- Jul 64° 50°
- Aug 64° 50°
- Sep 58° 47°
- Oct 51° 42°
- Nov 44° 36°
- Dec 41° 33°
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 Port Alexander each month?
July is the warmest month, with normal highs of 64°F; January the coldest, with normal lows of 32°F. The most precipitation falls in October (19.85 in), the least in June (6.65 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 40°F | 32°F | 36.0°F | 16.25 | 12.3 | 24 | <1 | 13 | 7 h 30 min |
| February | 41°F | 33°F | 36.7°F | 11.72 | 12.0 | 19 | <1 | 12 | 9 h 30 min |
| March | 43°F | 33°F | 37.9°F | 11.05 | 11.9 | 22 | <1 | 15 | 11 h 40 min |
| April | 50°F | 37°F | 43.2°F | 8.64 | 1.2 | 19 | <1 | 5 | 14 h 10 min |
| May | 57°F | 42°F | 49.2°F | 7.86 | 0.1 | 17 | <1 | <1 | 16 h 20 min |
| June | 61°F | 47°F | 54.1°F | 6.65 | 0.0 | 16 | <1 | <1 | 17 h 40 min |
| July | 64°F | 50°F | 57.2°F | 9.03 | 0.0 | 17 | <1 | <1 | 17 h 10 min |
| August | 64°F | 50°F | 57.2°F | 13.94 | 0.0 | 19 | <1 | <1 | 15 h 10 min |
| September | 58°F | 47°F | 52.6°F | 19.34 | 0.0 | 23 | <1 | <1 | 12 h 50 min |
| October | 51°F | 42°F | 46.3°F | 19.85 | 0.3 | 25 | <1 | 2 | 10 h 30 min |
| November | 44°F | 36°F | 40.3°F | 18.12 | 4.1 | 24 | <1 | 7 | 8 h 20 min |
| December | 41°F | 33°F | 37.2°F | 19.58 | 14.1 | 24 | <1 | 13 | 7 h |
| Year (annual) | 51°F | 40°F | 45.6°F | 162.03 | 56.0 | 248 | <1 | 68 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 4°C | 0°C | 2.2°C | 413 mm | 31 cm |
| February | 5°C | 0°C | 2.6°C | 298 mm | 30 cm |
| March | 6°C | 0°C | 3.3°C | 281 mm | 30 cm |
| April | 10°C | 3°C | 6.2°C | 219 mm | 3 cm |
| May | 14°C | 5°C | 9.6°C | 200 mm | 0 cm |
| June | 16°C | 8°C | 12.3°C | 169 mm | 0 cm |
| July | 18°C | 10°C | 14.0°C | 229 mm | 0 cm |
| August | 18°C | 10°C | 14.0°C | 354 mm | 0 cm |
| September | 15°C | 8°C | 11.4°C | 491 mm | 0 cm |
| October | 11°C | 5°C | 7.9°C | 504 mm | 1 cm |
| November | 7°C | 2°C | 4.6°C | 460 mm | 10 cm |
| December | 5°C | 1°C | 2.9°C | 497 mm | 36 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00507557; 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 Port Alexander?
No month's normal high reaches 65°F in Port Alexander: the warmest is July at 64°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 USC00507557.
When is the last frost in Port Alexander?
In Port Alexander, the last spring frost (32°F) comes after April 18 in half of years and after May 5 in one year in ten; the first autumn frost comes before November 5 in half of years and before October 16 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
- April 181 year in 10 after May 5; 9 in 10 after March 31
- First autumn frost, half of years before
- November 51 year in 10 before October 16; 9 in 10 before November 25
NOAA puts the median frost-free season at 198 days, and the season without a hard freeze (28°F) at 243 days.
A hard freeze (28°F) comes after March 26 in half of springs and before November 24 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Port Alexander in zone 8a in ZIP code 99836.
Frost dates for every NOAA station in Alaska · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00507557; 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 Port Alexander?
In a normal year in Port Alexander, a 90°F day is rare, 68 nights fall to 32°F or colder and 248 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
- 68a normal year
- Days that stay below freezing
- 10high of 32°F or less
- Days with 0.01 inch of precipitation
- 248a normal year
- Days with 1 inch of snow or more
- 16a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00507557.
How sunny is Port Alexander?
Over a year 58% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Port Alexander, 2.5 kWh per square metre a day. April is the sunniest month (63%) and December the cloudiest (47%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 48% | 0.4 |
| February | 56% | 1.1 |
| March | 59% | 2.3 |
| April | 63% | 3.7 |
| May | 63% | 4.7 |
| June | 59% | 4.8 |
| July | 56% | 4.2 |
| August | 59% | 3.6 |
| September | 57% | 2.4 |
| October | 53% | 1.3 |
| November | 49% | 0.6 |
| December | 47% | 0.3 |
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 Port Alexander need?
A normal year in Port Alexander brings 7,049 heating degree days, 31% more than the median U.S. place (5,373), and 2 cooling degree days, 100% 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 726 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 899 | 0 |
| February | 794 | 0 |
| March | 840 | 0 |
| April | 653 | 0 |
| May | 490 | 0 |
| June | 329 | 1 |
| July | 242 | 1 |
| August | 244 | 1 |
| September | 371 | 0 |
| October | 581 | 0 |
| November | 743 | 0 |
| December | 863 | 0 |
| Year (annual) | 7,049 | 2 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00507557. 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 Port Alexander's climate compare?
Port Alexander is warmer than 82 of the other 84 places with their own NOAA record in Alaska, and wetter than 71. Across the 7,247 U.S. stations with normals, its annual mean of 45.6°F is warmer than 22%.
In the Köppen classification computed from these normals, Port Alexander is Cfb: temperate, no dry season, warm 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 Port Alexander's climate
What is the coldest month in Port Alexander?
January, with a normal high of 40°F and a normal low of 32°F. The warmest is July (64°F by day, 50°F at night).
Does it snow in Port Alexander?
Yes: 56 inches in a normal year, falling on 24 days with 0.1 inch or more, the most in December (14.1 inches).
What is the rainiest month in Port Alexander?
October, with 19.85 in of precipitation in a normal year; the driest is June with 6.65 in.
What plant hardiness zone is Port Alexander in?
The USDA's 2023 map puts Port Alexander in zone 8a in ZIP code 99836.
How late can frost come in Port Alexander?
In half of years the last 32°F night comes after April 18; in one year in ten it comes after May 5. Waiting until May 5 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Alaska climateThe statewide normals and every place in the state
- Little Port Walter, AK9 miles from this station, 44.1°F a year
- Point Baker, AK40 miles from this station, 43.7°F a year
- Sitka, AK62 miles from this station, 45.4°F a year
- Hidden Falls Hatchery, AK68 miles from this station, 42.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made