Sitka, Alaska climate: Normal weather by month, frost dates and records
Sitka's normal year runs from 32°F January nights to 62°F August afternoons, with 84.5 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.4°C, January lows of 0°C, August highs of 17°C, 2,146 mm of precipitation a year.
- NOAA stationSitka Airport
- Station IDUSW00025333
- Location57.05°N 135.36°W
- Elevation14 ft (4 m)
- Population8,355
On October 23, the normal high in Sitka is 49°F and the normal low 40°F, and the chance of measurable rain or snow is 76%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sitka.
- Jan 41° 32°
- Feb 41° 32°
- Mar 43° 33°
- Apr 48° 37°
- May 53° 43°
- Jun 58° 48°
- Jul 60° 53°
- Aug 62° 53°
- Sep 58° 49°
- Oct 51° 42°
- Nov 44° 36°
- Dec 42° 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 Sitka each month?
August is the warmest month, with normal highs of 62°F; January the coldest, with normal lows of 32°F. The most precipitation falls in October (11.78 in), the least in June (2.92 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 41°F | 32°F | 36.5°F | 8.22 | 21 | <1 | 14 | 7 h 20 min |
| February | 41°F | 32°F | 36.7°F | 5.93 | 17 | <1 | 14 | 9 h 30 min |
| March | 43°F | 33°F | 37.5°F | 5.60 | 18 | <1 | 14 | 11 h 40 min |
| April | 48°F | 37°F | 42.6°F | 4.31 | 18 | <1 | 5 | 14 h 10 min |
| May | 53°F | 43°F | 48.1°F | 3.81 | 16 | <1 | <1 | 16 h 30 min |
| June | 58°F | 48°F | 53.0°F | 2.92 | 17 | <1 | <1 | 17 h 50 min |
| July | 60°F | 53°F | 56.5°F | 4.62 | 19 | <1 | <1 | 17 h 20 min |
| August | 62°F | 53°F | 57.3°F | 7.25 | 19 | <1 | <1 | 15 h 20 min |
| September | 58°F | 49°F | 53.2°F | 11.69 | 22 | <1 | <1 | 12 h 50 min |
| October | 51°F | 42°F | 46.4°F | 11.78 | 24 | <1 | 2 | 10 h 30 min |
| November | 44°F | 36°F | 40.0°F | 9.91 | 22 | <1 | 8 | 8 h 10 min |
| December | 42°F | 33°F | 37.5°F | 8.43 | 22 | <1 | 12 | 6 h 50 min |
| Year (annual) | 50°F | 41°F | 45.4°F | 84.47 | 235 | <1 | 70 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 5°C | 0°C | 2.5°C | 209 mm |
| February | 5°C | 0°C | 2.6°C | 151 mm |
| March | 6°C | 0°C | 3.1°C | 142 mm |
| April | 9°C | 3°C | 5.9°C | 109 mm |
| May | 12°C | 6°C | 8.9°C | 97 mm |
| June | 14°C | 9°C | 11.7°C | 74 mm |
| July | 16°C | 11°C | 13.6°C | 117 mm |
| August | 17°C | 12°C | 14.1°C | 184 mm |
| September | 14°C | 9°C | 11.8°C | 297 mm |
| October | 10°C | 5°C | 8.0°C | 299 mm |
| November | 7°C | 2°C | 4.4°C | 252 mm |
| December | 5°C | 1°C | 3.1°C | 214 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 USW00025333; 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 Sitka?
No month's normal high reaches 65°F in Sitka: the warmest is August 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 USW00025333.
When is the last frost in Sitka?
In Sitka, the last spring frost (32°F) comes after April 12 in half of years and after April 30 in one year in ten; the first autumn frost comes before November 1 in half of years and before October 13 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 121 year in 10 after April 30; 9 in 10 after March 28
- First autumn frost, half of years before
- November 11 year in 10 before October 13; 9 in 10 before November 21
NOAA puts the median frost-free season at 201 days, and the season without a hard freeze (28°F) at 242 days.
A hard freeze (28°F) comes after March 24 in half of springs and before November 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sitka in zone 7b in ZIP code 99835. By the map's own method, the average of each year's coldest night over 1991-2020, Sitka's NOAA station is in zone 8a: the coldest night of a typical year reaches 14°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 USW00025333; 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 Sitka?
In a normal year in Sitka, a 90°F day is rare, 70 nights fall to 32°F or colder and 235 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
- 70a normal year
- Days that stay below freezing
- 9high of 32°F or less
- Days with 0.01 inch of precipitation
- 235a normal year
The highest temperature in this station's record (since 1944) is 88°F, on July 30, 1976; the lowest is −1°F, on February 17, 1948.
The wettest calendar year on that record is 1961, with 122.96 in; the snowiest season is 1975–76, with 91.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00025333; records: ACIS (NOAA Regional Climate Centers), station USW00025333. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Sitka, and how clear are its skies?
The summer (June-August) dew point averages 51°F. The muggiest month is July, with an average dew point of 53°F; the driest air comes in February (28°F). November is the windiest month (9.6 mph on average), and February has the most clear or nearly clear hours (39%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 30°F | 77% | 73% | 8.8 mph | 26% | 61% |
| February | 28°F | 71% | 65% | 8.1 mph | 39% | 49% |
| March | 32°F | 74% | 67% | 7.9 mph | 30% | 51% |
| April | 38°F | 74% | 66% | 7.7 mph | 33% | 53% |
| May | 45°F | 81% | 75% | 6.8 mph | 31% | 59% |
| June | 50°F | 84% | 77% | 6.2 mph | – | – |
| July | 53°F | 86% | 79% | 5.9 mph | – | – |
| August | 51°F | 85% | 78% | 6.1 mph | – | – |
| September | 45°F | 83% | 76% | 7.4 mph | 24% | 60% |
| October | 37°F | 78% | 73% | 8.9 mph | 25% | 55% |
| November | 32°F | 77% | 75% | 9.6 mph | – | – |
| December | 30°F | 75% | 74% | 9.4 mph | 33% | 53% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00025333. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Sitka?
Over a year 55% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Sitka, 2.3 kWh per square metre a day. April is the sunniest month (61%) and December the cloudiest (45%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 46% | 0.4 |
| February | 55% | 1.1 |
| March | 58% | 2.2 |
| April | 61% | 3.6 |
| May | 60% | 4.5 |
| June | 55% | 4.5 |
| July | 51% | 3.9 |
| August | 54% | 3.3 |
| September | 52% | 2.2 |
| October | 49% | 1.2 |
| November | 46% | 0.5 |
| December | 45% | 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 Sitka need?
A normal year in Sitka brings 7,124 heating degree days, 33% more than the median U.S. place (5,373), and 1 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 680 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 885 | 0 |
| February | 794 | 0 |
| March | 853 | 0 |
| April | 671 | 0 |
| May | 522 | 0 |
| June | 362 | 0 |
| July | 266 | 0 |
| August | 238 | 1 |
| September | 354 | 0 |
| October | 578 | 0 |
| November | 749 | 0 |
| December | 854 | 0 |
| Year (annual) | 7,124 | 1 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00025333. 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 Sitka been warmer than normal lately?
2024 averaged 47.0°F, 1.6°F above the 1991-2020 normal of 45.4°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 45.3°F | −0.1°F | 86.93 |
| 2022 | 46.8°F | +1.4°F | 102.01 |
| 2023 | 47.7°F | +2.3°F | 105.42 |
| 2024 | 47.0°F | +1.6°F | 88.09 |
Over 73 complete years from 1948 to 2024, the station's annual mean temperature rose at a fitted 3.1°F per century (+0.17°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00025333; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Sitka's climate compare?
Sitka is warmer than 81 of the other 84 places with their own NOAA record in Alaska, and wetter than 60. Across the 7,247 U.S. stations with normals, its annual mean of 45.4°F is warmer than 21%.
In the Köppen classification computed from these normals, Sitka 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.
What do Sitka's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Sitka. This page uses Sitka Airport; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Sitka (1 mi NE) USW00025379 | 2 mi NE | 78 ft | 43.3°F | 29°F | 60°F | 102.1 | – | May 3 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Sitka's climate
What is the coldest month in Sitka?
January, with a normal high of 41°F and a normal low of 32°F. The warmest is August (62°F by day, 53°F at night).
What is the rainiest month in Sitka?
October, with 11.78 in of precipitation in a normal year; the driest is June with 2.92 in.
What plant hardiness zone is Sitka in?
The USDA's 2023 map puts Sitka in zone 7b in ZIP code 99835. By the same method at Sitka's NOAA station, the coldest night of a typical year reaches 14°F (28 years, 1991-2020): zone 8a.
How late can frost come in Sitka?
In half of years the last 32°F night comes after April 12; in one year in ten it comes after April 30. Waiting until April 30 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Sitka in OctoberThis month day by day, its records and recent years
- Alaska climateThe statewide normals and every place in the state
- Hidden Falls Hatchery, AK22 miles from this station, 42.3°F a year
- Little Port Walter, AK53 miles from this station, 44.1°F a year
- Port Alexander, AK62 miles from this station, 45.6°F a year
- Pelican, AK70 miles from this station, 42.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made