Late summer · Weather & things to do
San Juan Island in August
San Juan Island's warmest month brings highs averaging 70°F (21°C), lows of 57°F (14°C) and about 1.1 in (27 mm) of rain.
At 95/100 for comfort (2nd of 12), it's one of the best months to visit.
- Avg high
- 70°F (21°C)
- Avg low
- 57°F (14°C)
- Rain
- 1.1 in (27 mm)
- Humidity
- 74%
- Cloud cover
- 46%
- Daylight
- ~14 h 09 min
- Comfort score
- 95/100 · Great
What August feels like
Warm afternoons near 70°F (21°C) make long days outdoors easy.
After dark, temperatures fall to about 57°F (14°C).
Rain is scarce: about 1.1 in (27 mm) for the whole month.
Plan around August
August is one of San Juan Island's best months on the climate data.
- First warm month: highs reach 70°F, up from 70°F in July.
- Last warm month for a while: September highs fall to 65°F.
- Comfort holds steady from July (95 → 95/100).
- August sits inside the May – Sep window our Puget Sound Islands route recommends.
What to pack for August
- Light, breathable clothes70°F afternoons
- Sunscreen, sunglasses and a hathigh UV on clear days
- Comfortable walking shoesmost picks involve some walking
What to do in San Juan Island in August
August is good outdoor weather here, so these picks lean toward the open air.
Whale watching from Friday Harbor
Boat tours to find orcas, humpbacks and minke whales in Haro Strait.
Why now Our curated notes say it's best May–Sep.
Lime Kiln Point State Park
Lighthouse shoreline known as one of the best places to see orcas from land.
Why now Our curated notes say it's best summer afternoon.
American Camp
Open prairie and beaches from the 1859 Pig War, part of the national historical park.
Why now August scores 95/100 for comfort, good conditions for being outside.
English Camp
British garrison site with restored buildings and a Young Hill hike.
Why now Highs near 70°F and 1.1 in of monthly rain make this an easy outdoor pick.
The Farm at Krystal Acres
Working alpaca farm in the island's west valley, with pastures to walk and a barn shop of alpaca-wool goods.
Why now One to do outside while the weather is on your side.
Nearby in August
- Victoria in August~18 mi · highs 70°F, 1.1 in rain · similar daytime temperatures, about as wet
- Vancouver in August~52 mi · highs 75°F, 2.4 in rain · 3°C (5°F) warmer by day, wetter
- Olympic NP in August~57 mi · highs 59°F, 1.7 in rain · 6°C (11°F) cooler by day, wetter
- Bainbridge Island in August~67 mi · highs 75°F, 1.1 in rain · 3°C (5°F) warmer by day, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
San Juan Island in August: quick answers
Is August a good time to visit San Juan Island?
Yes. On the climate data it's one of the best months, scoring 95/100. Expect highs of 70°F (21°C) and 1.1 in (27 mm) of rain. August is inside the May – Sep window our Puget Sound Islands route recommends.
How hot is San Juan Island in August?
Average highs are 70°F (21°C) and average lows 57°F (14°C), making it the warmest month by daytime highs.
Does it rain a lot in San Juan Island in August?
Not much: about 1.1 in (27 mm) of rain falls across August on average, the 2nd-driest month of the year. The annual total is about 39.0 in (991 mm).
What should I pack for San Juan Island in August?
Bring light, breathable clothes (70°F afternoons), sunscreen, sunglasses and a hat (high UV on clear days) and comfortable walking shoes (most picks involve some walking).
More on San Juan Island
Routes in season in August
- Puget Sound Islands May – Sep
Planning San Juan Island in August?
Share this August plan with your group, poll everyone on dates and keep the packing list in one place.