Best time to visit Mercer Island, WA
A month-by-month travel weather guide based on NOAA 30-year climate normals.
The most comfortable travel window in Mercer Island runs from April through October — 7 months of pleasant temperatures and modest rainfall.
Frequent rain. Bring waterproof gear; outdoor plans need flexibility.
Daylight ≈ 8h 38m
Mild but on the chilly side. Pack a jacket; great for hiking and city walks.
Daylight ≈ 10h 0m
Mild but on the chilly side. Pack a jacket; great for hiking and city walks.
Daylight ≈ 11h 39m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 13h 24m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 14h 55m
Sweet spot — comfortable highs in the 65-80°F range, mild nights, low rain. Ideal for nearly any outdoor plan.
Daylight ≈ 15h 42m
Sweet spot — comfortable highs in the 65-80°F range, mild nights, low rain. Ideal for nearly any outdoor plan.
Daylight ≈ 15h 24m
Sweet spot — comfortable highs in the 65-80°F range, mild nights, low rain. Ideal for nearly any outdoor plan.
Daylight ≈ 14h 5m
Sweet spot — comfortable highs in the 65-80°F range, mild nights, low rain. Ideal for nearly any outdoor plan.
Daylight ≈ 12h 19m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 10h 35m
Frequent rain. Bring waterproof gear; outdoor plans need flexibility.
Daylight ≈ 9h 1m
Frequent rain. Bring waterproof gear; outdoor plans need flexibility.
Daylight ≈ 8h 15m
Looking for similar climates? See Mercer Island's climate twins. Or jump straight to the full climate profile.