Portland Weather in May

During May, Portland experiences moderate daytime temperatures of 18°C (64°F) and cooler nights around 8°C (46°F). Expect quite a bit of rainfall. Around 108 mm (4.3 in) is typical.

Rainfall in Portland in May

Historically, the month has about 13 days of rain, averaging 108 mm (4.3 in) in total. The rain this month tends to fall in heavier spells rather than light drizzle. When it rains, showers can be significant.

Temperature in Portland in May

Daytime temperatures in Portland reach 18°C (64°F) in May, dropping to 8°C (46°F) at night. The difference between afternoon and evening temperatures is usually noticeable. Nights fall to 8°C (46°F), which is cold enough to feel it indoors too. A good thick duvet makes all the difference for a comfortable night's sleep.

Sunshine in Portland in May

Expect sunny days throughout the month, with an estimated 244 hours of sunshine. This makes it a pleasant time to visit Portland.

Average water temperature in May

At 8°C (46°F), the water is too cold for most people to swim comfortably. A wetsuit is pretty much essential if you plan to go in.

If you prefer enjoying temperate temperatures and rain-free days, June, July, August and September typically offer the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.