May weather forecastPortland, ME
May
Weather in May
May brings about warmer temperatures, making it an enjoyable precursor to the summer. The mercury rises, hitting between 46.9°F (8.3°C) and 57.4°F (14.1°C). Portland, Maine in May experiences the city blossoming into a plethora of colors brought about by the blooming flora. The Maine Running Festival is an event to look out for this month. Many inhabitants enjoy the outdoors with sunny picnics in parks and along the beautiful Portland coastline.Temperature
With the onset of May, Portland sees a temperature rise, with the average high-temperature moving from April's frosty 47.8°F (8.8°C) to a mild 57.4°F (14.1°C). Throughout May, Portland experiences a low-temperature average of 46.9°F (8.3°C).Humidity
In Portland, the average relative humidity in May is 81%.Rainfall
In Portland, in May, during 13.2 rainfall days, 1.85" (47mm) of precipitation is typically accumulated. Throughout the year, in Portland, Maine, there are 127 rainfall days, and 21.93" (557mm) of precipitation is accumulated.Snowfall
In Portland, snow does not fall in May through September.Ocean temperature
In Portland, Maine, in May, the average water temperature is 46.6°F (8.1°C).Note: You can swim in 46.6°F (8.1°C) below 50°F (10°C) with proper thermal wear; failing that, the cold shock and respiratory challenges are nearly certain. A short span at 55.4°F (13°C) without it is tough.
Daylight
In May, the average length of the day is 14h and 44min.On the first day of the month, sunrise is at 5:32 am and sunset at 7:43 pm. On the last day of May, sunrise is at 5:02 am and sunset at 8:15 pm EDT.
Sunshine
In May, the average sunshine in Portland is 8.4h.UV index
The average daily maximum UV index in May in Portland is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for the average person.Note: A maximum daily UV index of 4 during May morphs into the following directions:
Undertake protective steps - Recommendations to avoid sunburn are issued. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Portland, ME
- Average high temperature in May: 57.4°F
The warmest month (with the highest average high temperature) is July (72.5°F).
The month with the lowest average high temperature is January (31.1°F).
- Average low temperature in May: 46.9°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (20.7°F).
Average pressure in May
Portland, ME
- Average pressure in May: 29.99"Hg
The months with the highest atmospheric pressure are September and November (30.05"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in May
Portland, ME
- Average wind speed in May: 9mph
The windiest month (with the highest average wind speed) is January (12.5mph).
The calmest months (with the lowest average wind speed) are July and August (7.5mph).
Average humidity in May
Portland, ME
- Average humidity in May: 81%
The months with the highest relative humidity are June and July (82%).
The month with the lowest relative humidity is November (74%).
Average rainfall in May
Portland, ME
- Average rainfall in May: 1.85"
The wettest month (with the highest rainfall) is October (2.36").
The driest month (with the least rainfall) is September (1.18").
Average rainfall days in May
Portland, ME
- Average rainfall days in May: 13.2 days
The month with the highest number of rainy days is July (14.7 days).
The month with the least rainy days is January (5.7 days).
Average snowfall in May
Portland, ME
- Average snowfall in May: 0"
The month with the highest snowfall is February (2.91").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in May
Portland, ME
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is January (7.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in May
Portland, ME
- Average sea temperature in May: 46.7°F
The best month for swimming (with the highest average sea temperature) is August (63.7°F).
The coldest month (with the lowest average sea temperature) is March (38°F).
Average daylight in May /
Average sunshine in May
Portland, ME
- Average daylight in May: 14h and 42min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in May: 8h and 24min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 48min).
Average sunshine days in May
Portland, ME
- Average sunshine days in May: 16 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is July (13.8 days).
Average UV index in May
Portland, ME
- Average UV index in May: 4
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in May
Portland, ME
- Average cloud cover in May: 45
The month with the most cloud cover is March (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in May
Portland, ME
- Average visibility in May: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
