May weather forecast and climate
Belfast, ME

Weather in May

May, the last month of the spring, in Belfast, is a mild month, with temperature in the range of an average high of 59.7°F (15.4°C) and an average low of 43.9°F (6.6°C).

Temperature

In May, the average high-temperature increases, from a chilly 48.9°F (9.4°C) in April, to a moderate 59.7°F (15.4°C). The average low-temperature, in Belfast, is 43.9°F (6.6°C).

Humidity

In May, the average relative humidity is 80%.

Rainfall

In Belfast, it is raining for 15.3 days, with typically 2.05" (52mm) of accumulated precipitation. Throughout the year, there are 141.1 rainfall days, and 24.29" (617mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Belfast are January through May, October through December. May is the last month it regularly snows in Belfast, Maine. During 0.1 snowfall days, Belfast aggregates 0.35" (9mm) of snow. Throughout the year, there are 44.3 snowfall days, and 16.81" (427mm) of snow is accumulated.

Ocean temperature

In Belfast, the average seawater temperature is 45.1°F (7.3°C).
Note: At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

Daylight

In May, the average length of the day is 14.8h.

Sunshine

The average sunshine in May is 7.6h.

UV index

In May, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 4 interpret into the following advice:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the average humidity in May in Belfast?

In May, the average relative humidity in Belfast is 80%.

How many days does it rain in May in Belfast?

In Belfast, during May, the rain falls for 15.3 days and regularly aggregates up to 2.05" (52mm) of precipitation.

What is the last month it snows in Belfast?

May is the last month it regularly snows in Belfast, Maine. During 0.1 snowfall days, in May, Belfast aggregates 0.35" (9mm) of snow.

How cold is the water in May in Belfast?

In Belfast, in May, the average water temperature is 45.1°F (7.3°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the average length of the day in May in Belfast?

The average length of the day in May in Belfast, Maine, is 14.8h.

How many hours of sunshine does Belfast have in May?

The average sunshine in May is 7.6h.

How high is the UV index in May in Belfast?

The average daily maximum UV index in May in Belfast, Maine, is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from the exposure to the Sun's UV radiation.

Average temperature in May
Belfast, ME

Average temperature in May - Belfast, ME
  • Average high temperature in May: 59.7°F

The warmest months (with the highest average high temperature) are July and August (73.9°F).
The month with the lowest average high temperature is January (28.4°F).

  • Average low temperature in May: 43.9°F

The month with the highest average low temperature is July (57.7°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).

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Average pressure in May
Belfast, ME

Average pressure in May - Belfast, ME
  • Average pressure in May: 29.99"

The month with the highest atmospheric pressure is September (30.04").
The month with the lowest atmospheric pressure is June (29.91").

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Average wind speed in May
Belfast, ME

Average wind speed in May - Belfast, ME
  • Average wind speed in May: 7.6mph

The windiest month (with the highest average wind speed) is March (10.1mph).
The calmest months (with the lowest average wind speed) are July and August (6mph).

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Average humidity in May
Belfast, ME

Average humidity in May - Belfast, ME
  • Average humidity in May: 80%

Months with the highest relative humidity are February and July (83%).
The month with the lowest relative humidity is November (77%).

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Average rainfall in May
Belfast, ME

Average rainfall in May - Belfast, ME
  • Average rainfall in May: 2.05"

The wettest month (with the highest rainfall) is December (2.72").
The driest months (with the least rainfall) are July and September (1.46").

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Average rainfall days in May
Belfast, ME

Average rainfall days in May - Belfast, ME
  • Average rainfall days in May: 15.3 days

The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (7.1 days).

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Average snowfall in May
Belfast, ME

Average snowfall in May - Belfast, ME
  • Average snowfall in May: 0.35"

The month with the highest snowfall is January (4.57").
Months with the least snowfall are June, July, August and September (0").

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Average snowfall days in May
Belfast, ME

Average snowfall days in May - Belfast, ME
  • Average snowfall days in May: 0.1 days

The month with the highest number of snowfall days is January (10.1 days).
Months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in May
Belfast, ME

Average sea temperature in May - Belfast, ME
  • Average sea temperature in May: 45.1°F

The best month for swimming (with the highest average sea temperature) is August (60.4°F).
The coldest month (with the lowest average sea temperature) is March (37.8°F).

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Average daylight in May /
Average sunshine in May
Belfast, ME

Average daylight in May / Average sunshine in May - Belfast, ME
  • Average daylight in May: 14.8h

The month with the longest days is June (Average daylight: 15.5h).
The month with the shortest days is December (Average daylight: 8.9h).

  • Average sunshine in May: 7.6h

The month with the most sunshine is August (Average sunshine: 9.9h).
The month with the least sunshine is February (Average sunshine: 4.3h).

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Average sunshine days in May
Belfast, ME

Average sunshine days in May - Belfast, ME
  • Average sunshine days in May: 13.7 days

The month with the most sunshine days is September (17.9 days).
The month with the least sunshine days is April (11.7 days).

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Average UV index in May
Belfast, ME

Average UV index in May - Belfast, ME
  • Average UV index in May: 4

Months with the highest UV index are June, July and August (UV index 5).
Months with the lowest UV index are January, February, March, November and December (UV index 2).

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Average cloud cover in May
Belfast, ME

Average cloud cover in May - Belfast, ME
  • Average cloud cover in May: 51

The month with the most cloud cover is March (Cloud cover 55).
Months with the least cloud cover are August and September (Cloud cover 37).

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Average visibility in May
Belfast, ME

Average visibility in May - Belfast, ME
  • Average visibility in May: 5mi

Months with the highest visibility are January, February, March, April, October, November and December (6mi).
Months with the lowest visibility are May, June, July, August and September (5mi).

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