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Friday Harbor climate
Typical historical weather for Friday Harbor, United States, averaged across 10 years of hourly climate data. Pick a date for a specific day.
Data last updated: 31 December 2025
Want today's actual conditions instead? See the current forecast for Friday Harbor. Planning a garden? See the gardening & growing season planner. Or browse the 365-day climate calendar.
Annual average
10.7°C
across all months
Warmest month
17.6°C
Aug average high
Coolest month
4.8°C
Feb average low
Annual rainfall
1246mm
total per year
Friday Harbor is typically hottest in August and coolest in February, a swing of about 12.8°C across the year. About 42% of annual rainfall falls in the three wettest months (November is typically wettest, July driest).
Monthly averages
Average daily high/low temperature (band) and monthly rainfall (bars).
| Month | Avg high | Avg low | Rainfall | Wet days | Humidity | Wind | Cloud | Solar |
|---|---|---|---|---|---|---|---|---|
| Jan | 7.7°C · record 9.3°C–13.3°C | 5.5°C · record -7.4°C–4°C | 159mm | 19 | 81% | 4.9 m/s | 78% | 1.1 kWh/m² |
| Feb | 7.2°C · record 9.3°C–12.1°C | 4.8°C · record -3°C–4.6°C | 138mm | 20 | 78% | 4.1 m/s | 75% | 1.8 kWh/m² |
| Mar | 8.9°C · record 10.6°C–14.1°C | 6.4°C · record 1.8°C–5.2°C | 119mm | 18 | 79% | 3.8 m/s | 69% | 3.1 kWh/m² |
| Apr | 10.8°C · record 12.5°C–17.1°C | 8.3°C · record 3.3°C–8.1°C | 91mm | 16 | 78% | 3.6 m/s | 66% | 4.5 kWh/m² |
| May | 13.3°C · record 14.4°C–21.1°C | 10.8°C · record 6.2°C–9.6°C | 57mm | 10 | 80% | 3.1 m/s | 59% | 5.7 kWh/m² |
| Jun | 15°C · record 17.7°C–23.7°C | 12.4°C · record 9.1°C–10.7°C | 56mm | 10 | 80% | 3 m/s | 57% | 6 kWh/m² |
| Jul | 16.9°C · record 18.3°C–20.9°C | 14.1°C · record 11.8°C–12.9°C | 23mm | 6 | 80% | 3.1 m/s | 37% | 6.4 kWh/m² |
| Aug | 17.6°C · record 20.7°C–21.9°C | 14.8°C · record 11.9°C–13.6°C | 32mm | 6 | 80% | 2.9 m/s | 41% | 5.6 kWh/m² |
| Sep | 15.7°C · record 18°C–22°C | 13.4°C · record 10.1°C–12.6°C | 66mm | 11 | 82% | 2.9 m/s | 52% | 3.9 kWh/m² |
| Oct | 12.7°C · record 14°C–18.3°C | 10.5°C · record 5.1°C–8.8°C | 136mm | 16 | 82% | 3.7 m/s | 62% | 2.3 kWh/m² |
| Nov | 9.9°C · record 12.3°C–16.4°C | 7.9°C · record 1.2°C–7.5°C | 186mm | 20 | 82% | 4.7 m/s | 76% | 1.2 kWh/m² |
| Dec | 7.8°C · record 9.7°C–13.6°C | 5.6°C · record -6.4°C–4.5°C | 184mm | 20 | 81% | 4.8 m/s | 79% | 0.8 kWh/m² |
"Avg high"/"Avg low" is the mean daily high/low for that month, averaged across every year on file. The "record" figure alongside it is a different statistic — the single hottest (or coldest) hour ever recorded during that month across all years — so it can sit above or below the average and does not describe the average's year-to-year spread. A "wet day" is any day with at least 1.0mm of rain.
Year to year
Annual average temperature, 2016–2025.
Across these 10 years, the annual average has moved by about -0.2°C per decade. That’s a short window for a reliable long-term climate trend — treat it as indicative, not definitive.
Annual rainfall has moved by about -116.11mm per decade over the same period.
2025 (the most recent year on file) averaged 10.9°C, above the 9-year baseline of 10.7°C by 0.73 standard deviations.
Typical extremes per year
Rainy days
171.4 days
≥1.0mm rain
Heavy rain days
8 days
≥20mm rain
Extreme heat days
0 days
daily high ≥40°C
Frost days
3.7 days
daily low ≤0°C
Averaged across 10 years on file. Thresholds match PastClimate's data pipeline definitions — see data & sources.
Records on file
Ranked across 10 years of data currently on file (2016–2025).
Hottest day
23.7°C
28 June 2021
2021 was 0.59 SD below the 9-year average that year
Coldest day
-7.4°C
12 January 2024
2024 was 0.05 SD above the 9-year average that year
Wettest day
50.4mm
21 December 2020
2020 was 0.03 SD below the 9-year average that year
Windiest day
11.6m/s
2 January 2022
2022 was 1.97 SD below the 9-year average that year
See the detail: Friday Harbor on 21 December 2020.
Nearby cities
Frequently asked questions about Friday Harbor's climate
What is the hottest month in Friday Harbor?
August is typically the warmest month in Friday Harbor, with an average high of 17.6°C. February is typically the coolest, averaging 4.8°C overnight.
How much does it rain in Friday Harbor?
Friday Harbor gets about 1246mm of rain a year on average, with roughly 42% of it falling in the three wettest months (November is typically the wettest, July the driest).
How many extremely hot or cold days does Friday Harbor have?
On average, Friday Harbor sees about 0 day(s) a year at or above 40°C and about 3.7 day(s) at or below 0°C, based on 10 years of data.
Is Friday Harbor getting warmer?
Across the 10 years on file (2016–2025), the annual average temperature has moved by about -0.17°C per decade. That's a short window for a reliable long-term climate trend — treat it as indicative, not definitive.
What is the hottest day on record for Friday Harbor?
The hottest day on file is 28 June 2021 at 23.7°C, out of 10 year(s) searched.
Data & provenance
↓ Download monthly CSVData source & coverage — ERA5 reanalysis, 2016–2025 (10 years)details
- Source
- ERA5 reanalysis, accessed via the Copernicus Climate Change Service (C3S) Climate Data Store
- Data type
- Reanalysis — a physically consistent reconstruction combining a forecast model with historical observations, not a live station reading or a forecast
- Coverage
- 2016–2025 (10 years) for United States
- Location
- Friday Harbor — 48.250°, -122.750°, ERA5 grid cell center, 37.3 km from requested point
- Time zone
- America/Los_Angeles
- What's shown here
- Monthly and annual averages, and dated extreme-value records, derived from an hourly base record.
- Spatial resolution
- 0.25° (~25 km) distributed grid — ERA5's native model resolution is finer; this is the publicly distributed regridded product
- Version / refreshed
- Methodology v2026.07 · data last refreshed December 31, 2025
- Limitations
- A model reconstruction, not a station observation — hyper-local extremes (a single storm cell, an urban heat pocket) can differ from a nearby gauge. See the full methodology.
- Attribution
- Generated using Copernicus Climate Change Service information
Cite this data
PastClimate (2026-07-19). Historical climate data for Friday Harbor, United States (48.25°N, 122.75°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Friday Harbor, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 19, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Friday Harbor, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 19, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Friday Harbor, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-19},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.