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Portland weather in May 2025
Expect 64°F daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in Portland in May. Check more long-term weather averages for Portland in May before you book your next holiday to Maine in 2025/2026.
- 6464°F max day temperature
- 8 hours of sunshine per day
- 1212 days with some rainfall
- 4343°F min night temperature
- 1515 hours of daylight per day
- 0No heat & humidity
- 3.63.6 inches of monthly rainfall
- 77 (High) UV index
- 4646°F sea temperature
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Expires at 23:59 on Wednesday 31st Dec 2025 · View all Avalon Waterways offers
The May weather guide for Maine (Portland) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.
Metric (°C) | Imperial (°F)
More about the USA
How hot is it in Portland in May?
Daytime temperatures usually reach 64°F in Portland in May, falling to 43°F at night.
How sunny is it in Portland in May?
There are normally 8 hours of bright sunshine each day in Portland in May - that's 52% of daylight hours.
How warm is the sea around Portland in May?
The average sea temperature around Portland in May is 46°F.
Does it rain in Portland in May?
There are usually 12 days with some rain in Portland in May and the average monthly rainfall is 3.6 inches.
Portland May sunrise & sunset times
Browse the sunrise and sunset times for Portland in May 2025. Select a month to view Portland sunrise and sunset times for the next 12 months.
JanFebMarAprMayJunJulAugSepOctNovDec
Date | Sunrise times | Sunset times |
---|---|---|
Thursday, 1st May 2025 | 04:33 | 18:44 |
Friday, 16th May 2025 | 04:15 | 19:01 |
Saturday, 31st May 2025 | 04:03 | 19:15 |
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