Late spring · Weather & things to do
San Juan Island in May
San Juan Island warms up: highs climb to 60°F (15°C), from 53°F in April, with lows of 49°F (9°C) and about 2.0 in (52 mm) of rain.
It scores 78/100 for comfort, 5th of 12, which makes it a solid shoulder-season month.
- Avg high
- 60°F (15°C)
- Avg low
- 49°F (9°C)
- Rain
- 2.0 in (52 mm)
- Humidity
- 79%
- Cloud cover
- 67%
- Daylight
- ~15 h 01 min
- Comfort score
- 78/100 · Great
What May feels like
Highs near 60°F (15°C) make for comfortable sightseeing weather.
After dark, temperatures fall to about 49°F (9°C).
Rain is moderate at about 2.0 in (52 mm) for the month.
Long days help: there are roughly 15 h 01 min of daylight mid-month.
Plan around May
May is shoulder season: good weather, a step below the best months (June – September).
- The year's biggest warm-up: highs jump 4°C (6°F) from April.
- Comfort improves from 63/100 in April to 78/100.
- May sits inside the May – Sep window our Puget Sound Islands route recommends.
What to pack for May
- A warm layer for eveningsnights drop to 49°F
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in San Juan Island in May
With conditions on your side, the picks below favor time outside.
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.
San Juan Island Brewing Company
Brewpub two blocks from the ferry with pizzas and a patio.
Why now May scores 78/100 for comfort, good conditions for being outside.
Roche Harbor
Historic marina village with a flag ceremony at sunset in summer.
The Whale Museum
Small Friday Harbor museum on the Southern Resident orcas and local research.
Duck Soup
Long-running island restaurant using local produce and seafood.
Nearby in May
- Victoria in May~18 mi · highs 60°F, 2.0 in rain · similar daytime temperatures, about as wet
- Vancouver in May~52 mi · highs 63°F, 3.8 in rain · 2°C (4°F) warmer by day, wetter
- Olympic NP in May~57 mi · highs 48°F, 3.4 in rain · 6°C (11°F) cooler by day, wetter
- Bainbridge Island in May~67 mi · highs 64°F, 2.8 in rain · 3°C (5°F) warmer by day, wetter
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 May: quick answers
Is May a good time to visit San Juan Island?
It's a good shoulder-season choice, scoring 78/100 against a best of 95 in June – September. Expect highs of 60°F (15°C) and 2.0 in (52 mm) of rain. May is inside the May – Sep window our Puget Sound Islands route recommends.
How cold is San Juan Island in May?
Average highs are 60°F (15°C) and average lows 49°F (9°C), making it the 5th-warmest month by daytime highs.
Does it rain a lot in San Juan Island in May?
Not much: about 2.0 in (52 mm) of rain falls across May on average, the 5th-driest month of the year. The annual total is about 39.0 in (991 mm).
What should I pack for San Juan Island in May?
Bring a warm layer for evenings (nights drop to 49°F) and comfortable walking shoes (most places below are best reached on foot or with short walks).
More on San Juan Island
Routes in season in May
- Puget Sound Islands May – Sep
Planning San Juan Island in May?
Share this May plan with your group, poll everyone on dates and keep the packing list in one place.