Friday Harbor, Washington climate: Normal weather by month, frost dates and records
Friday Harbor's normal year runs from 37°F December nights to 73°F August afternoons, with 18.5 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.5°C, December lows of 3°C, August highs of 23°C, 469 mm of precipitation a year.
- NOAA stationFriday Harbor Airport
- Station IDUSW00094276
- Location48.52°N 123.02°W
- Elevation109 ft (33 m)
- Population2,744
On October 23, the normal high in Friday Harbor is 56°F and the normal low 43°F, and the chance of measurable rain or snow is 52%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Friday Harbor.
- Jan 47° 37°
- Feb 49° 37°
- Mar 53° 38°
- Apr 57° 41°
- May 64° 44°
- Jun 68° 48°
- Jul 72° 50°
- Aug 73° 50°
- Sep 68° 48°
- Oct 59° 44°
- Nov 51° 40°
- Dec 46° 37°
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 Friday Harbor each month?
August is the warmest month, with normal highs of 73°F; December the coldest, with normal lows of 37°F. The most precipitation falls in November (2.98 in), the least in July (0.48 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 47°F | 37°F | 42.1°F | 2.69 | 17 | <1 | 8 | 8 h 40 min |
| February | 49°F | 37°F | 42.5°F | 1.54 | 14 | <1 | 9 | 10 h 10 min |
| March | 53°F | 38°F | 45.5°F | 1.35 | 14 | <1 | 6 | 11 h 50 min |
| April | 57°F | 41°F | 49.1°F | 1.01 | 10 | <1 | 2 | 13 h 40 min |
| May | 64°F | 44°F | 54.0°F | 1.14 | 10 | <1 | <1 | 15 h 10 min |
| June | 68°F | 48°F | 58.2°F | 0.75 | 8 | <1 | <1 | 16 h 10 min |
| July | 72°F | 50°F | 61.2°F | 0.48 | 5 | <1 | <1 | 15 h 50 min |
| August | 73°F | 50°F | 61.6°F | 0.70 | 8 | <1 | <1 | 14 h 20 min |
| September | 68°F | 48°F | 58.0°F | 1.04 | 12 | <1 | <1 | 12 h 40 min |
| October | 59°F | 44°F | 51.2°F | 2.34 | 15 | <1 | 1 | 11 h |
| November | 51°F | 40°F | 45.4°F | 2.98 | 16 | <1 | 5 | 9 h 20 min |
| December | 46°F | 37°F | 41.6°F | 2.45 | 16 | <1 | 9 | 8 h 20 min |
| Year (annual) | 59°F | 43°F | 50.9°F | 18.47 | 144 | 1 | 40 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 8°C | 3°C | 5.6°C | 68 mm |
| February | 9°C | 3°C | 5.8°C | 39 mm |
| March | 11°C | 4°C | 7.5°C | 34 mm |
| April | 14°C | 5°C | 9.5°C | 26 mm |
| May | 18°C | 7°C | 12.2°C | 29 mm |
| June | 20°C | 9°C | 14.6°C | 19 mm |
| July | 22°C | 10°C | 16.2°C | 12 mm |
| August | 23°C | 10°C | 16.4°C | 18 mm |
| September | 20°C | 9°C | 14.4°C | 26 mm |
| October | 15°C | 7°C | 10.7°C | 59 mm |
| November | 11°C | 4°C | 7.4°C | 76 mm |
| December | 8°C | 3°C | 5.3°C | 62 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Olga (2 mi SE) (12 miles away), gets 6 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094276; 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 Friday Harbor?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, July has the fewest days with rain (5).
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 USW00094276.
When is the last frost in Friday Harbor?
In Friday Harbor, the last spring frost (32°F) comes after March 26 in half of years and after April 21 in one year in ten; the first autumn frost comes before November 10 in half of years and before October 21 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
- March 261 year in 10 after April 21; 9 in 10 after February 25
- First autumn frost, half of years before
- November 101 year in 10 before October 21; 9 in 10 before December 1
NOAA puts the median frost-free season at 230 days, and the season without a hard freeze (28°F) at 289 days.
A hard freeze (28°F) comes after February 22 in half of springs and before December 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Friday Harbor in zone 9a in ZIP code 98250, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Friday Harbor's NOAA station is in zone 8b: the coldest night of a typical year reaches 19°F (23 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 Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00094276; 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 Friday Harbor?
In a normal year in Friday Harbor, 1 day a year reaches 90°F, 40 nights fall to 32°F or colder and 144 days bring measurable precipitation.
- Days at 90°F or more
- 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 40a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 144a normal year
The highest temperature in this station's record (since 1998) is 101°F, on June 28, 2021; the lowest is 8°F, on December 20, 2008.
The wettest calendar year on that record is 2024, with 25.96 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00094276; records: ACIS (NOAA Regional Climate Centers), station USW00094276. Records use complete months only; a month missing more than three days is left out.
How sunny is Friday Harbor?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Friday Harbor, 3.5 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (51%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 52% | 1.0 |
| February | 61% | 1.9 |
| March | 61% | 2.9 |
| April | 67% | 4.3 |
| May | 71% | 5.5 |
| June | 72% | 6.0 |
| July | 82% | 6.5 |
| August | 81% | 5.5 |
| September | 76% | 3.9 |
| October | 64% | 2.2 |
| November | 55% | 1.1 |
| December | 51% | 0.8 |
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 Friday Harbor need?
A normal year in Friday Harbor brings 5,171 heating degree days, 4% fewer than the median U.S. place (5,373), and 32 cooling degree days, 97% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,470 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 710 | 0 |
| February | 630 | 0 |
| March | 605 | 0 |
| April | 479 | 0 |
| May | 341 | 0 |
| June | 207 | 5 |
| July | 130 | 12 |
| August | 116 | 12 |
| September | 213 | 3 |
| October | 426 | 0 |
| November | 588 | 0 |
| December | 727 | 0 |
| Year (annual) | 5,171 | 32 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094276. 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 Friday Harbor been warmer than normal lately?
2024 averaged 53.2°F, 2.3°F above the 1991-2020 normal of 50.9°F. 2 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.3°F | −0.6°F | 21.09 |
| 2022 | 50.1°F | −0.8°F | 19.24 |
| 2023 | 52.6°F | +1.8°F | 14.00 |
| 2024 | 53.2°F | +2.3°F | 25.96 |
Source: observed years: ACIS, station USW00094276. A year counts only with all twelve months complete.
How does Friday Harbor's climate compare?
Friday Harbor is warmer than 55 of the other 95 places with their own NOAA record in Washington, and wetter than 38. Across the 7,247 U.S. stations with normals, its annual mean of 50.9°F is warmer than 44%.
In the Köppen classification computed from these normals, Friday Harbor is Csb: temperate, dry-summer, 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.
Which places near Friday Harbor share this climate record?
Roche Harbor has no NOAA station with 1991-2020 normals of its 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.
- Roche Harbor, WA700 people · 8 mi NW
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 Friday Harbor's climate
What is the coldest month in Friday Harbor?
December, with a normal high of 46°F and a normal low of 37°F. The warmest is August (73°F by day, 50°F at night).
Does it snow in Friday Harbor?
Yes. NOAA publishes no 1991-2020 snowfall normal for Friday Harbor's NOAA station; the nearest record that keeps one, Olga (2 mi SE) (12 miles away), records 6 inches of snow in a normal year.
What is the rainiest month in Friday Harbor?
November, with 2.98 in of precipitation in a normal year; the driest is July with 0.48 in.
What plant hardiness zone is Friday Harbor in?
The USDA's 2023 map puts Friday Harbor in zone 9a in ZIP code 98250, the nearest ZIP area. By the same method at Friday Harbor's NOAA station, the coldest night of a typical year reaches 19°F (23 years, 1991-2020): zone 8b.
How late can frost come in Friday Harbor?
In half of years the last 32°F night comes after March 26; in one year in ten it comes after April 21. Waiting until April 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Washington climateThe statewide normals and every place in the state
- Olga (2 mi SE), WA12 miles from this station, 50.8°F a year
- Anacortes, WA19 miles from this station, 52.8°F a year
- Whidbey Island Naval Air Station, WA21 miles from this station, 52.1°F a year
- Coupeville, WA27 miles from this station, 50.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made