Late spring · Weather & things to do
Portland, Maine in May
Portland, Maine warms up: highs climb to 54°F (12°C), from 46°F in April, with lows of 47°F (8°C) and about 4.0 in (101 mm) of rain.
Our comfort score puts it mid-table at 63/100, 6th of 12.
- Avg high
- 54°F (12°C)
- Avg low
- 47°F (8°C)
- Rain
- 4.0 in (101 mm)
- Humidity
- 87%
- Cloud cover
- 66%
- Daylight
- ~14 h 32 min
- Comfort score
- 63/100 · Good
What May feels like
Cool days top out near 54°F (12°C), better for brisk walks than lingering outside.
Nights cool to an average low of 47°F (8°C).
Showers are part of the month, adding up to about 4.0 in (101 mm).
Plan around May
May sits mid-table; the best months are September.
- Comfort improves from 49/100 in April to 63/100.
- May sits inside the May – Oct window our Boston to Portland route recommends.
What to pack for May
- Insulated jackethighs only 54°F
- Packable rain jacket or umbrellaa shower or two is likely
- Comfortable walking shoesmost picks involve some walking
What to do in Portland, Maine in May
May is good outdoor weather here, so these picks lean toward the open air.
Portland Head Light
Maine's oldest lighthouse (1791) on cliffs in Fort Williams Park.
Why now May scores 63/100 for comfort, good conditions for being outside.
Portland Museum of Art
Strong Winslow Homer and Maine art collection in the Arts District.
Allagash Brewing Company
Belgian-style brewery with a tasting room and free tours.
The Holy Donut
Maine potato donuts in flavors like dark chocolate sea salt.
Eastern Promenade
Hilltop park and trail with views over Casco Bay and its islands.
Why now Highs near 54°F and 4.0 in of monthly rain make this an easy outdoor pick.
Nearby in May
- Portsmouth in May~48 mi · highs 58°F, 4.0 in rain · 2°C (4°F) warmer by day, about as wet
- Maine in May~51 mi · highs 65°F, 4.1 in rain · 6°C (11°F) warmer by day, about as wet
- White Mountains in May~67 mi · highs 44°F, 4.3 in rain or snow · 5°C (10°F) cooler by day, about as wet
- New Hampshire in May~73 mi · highs 67°F, 3.7 in rain · 8°C (14°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.
Portland, Maine in May: quick answers
Is May a good time to visit Portland, Maine?
It's middling, scoring 63/100. The best months are September, at up to 87. Expect highs of 54°F (12°C) and 4.0 in (101 mm) of rain. May is inside the May – Oct window our Boston to Portland route recommends.
How cold is Portland, Maine in May?
Average highs are 54°F (12°C) and average lows 47°F (8°C), making it the 6th-warmest month by daytime highs.
Does it rain a lot in Portland, Maine in May?
Some: about 4.0 in (101 mm) of rain falls across May on average, the 4th-driest month of the year. The annual total is about 53.7 in (1363 mm).
What should I pack for Portland, Maine in May?
Bring insulated jacket (highs only 54°F), packable rain jacket or umbrella (a shower or two is likely) and comfortable walking shoes (most picks involve some walking).
More on Portland, Maine
Routes in season in May
- Boston to Portland May – Oct
Planning Portland, Maine in May?
Plan it together in TripsCircle: one itinerary, one shared packing list and costs split as you go.