May weather forecast
Boston, MA

A beautiful natural park with the George Washington Monument in Boston, Massachusetts
A beautiful natural park with the George Washington Monument in Boston, Massachusetts

Weather in May

The last month of the spring, May, is an enjoyable month in Boston, Massachusetts, with temperature in the range of an average high of 66.4°F (19.1°C) and an average low of 50°F (10°C).

Temperature

In May, the average high-temperature rises from a cool 55.2°F (12.9°C) in April to an enjoyable 66.4°F (19.1°C). In May, in Boston, the average low-temperature is 50°F (10°C).

Humidity

In May, the average relative humidity in Boston is 72%.

Rainfall

In Boston, it is raining for 15.3 days, with typically 1.81" (46mm) of accumulated precipitation. Throughout the year, in Boston, there are 141.4 rainfall days, and 27.2" (691mm) of precipitation is accumulated.

Snowfall

January through May, October through December are months with snowfall in Boston. May is the last month it regularly snows. During 0.1 snowfall days, Boston aggregates 0.04" (1mm) of snow. Throughout the year, in Boston, there are 29.8 snowfall days, and 15.75" (400mm) of snow is accumulated.

Ocean temperature

In Boston, the average water temperature is 49.1°F (9.5°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 14h and 37min.
On the first day of the month, sunrise is at 5:38 am and sunset at 7:43 pm. On the last day of May, sunrise is at 5:10 am and sunset at 8:13 pm EDT.

Sunshine

In Boston, the average sunshine in May is 8.3h.

UV index

In Boston, the average daily maximum UV index in May is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The average daily UV index of 5 in May transform into the following instructions:
Take precautions - Protection against skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the average humidity in May in Boston?

The average relative humidity in May in Boston, Massachusetts, is 72%.

How many days does it rain in May in Boston?

In Boston, Massachusetts, during May, the rain falls for 15.3 days and regularly aggregates up to 1.81" (46mm) of precipitation.

What is the last month it snows in Boston?

May is the last month it regularly snows. During 0.1 snowfall days, in May, Boston aggregates 0.04" (1mm) of snow.

What is the ocean temperature in May in Boston?

In May, the average ocean temperature is 49.1°F (9.5°C). Swimming in 49.1°F (9.5°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

How many hours of daylight does Boston have in May?

In Boston, the average day length in May is 14h and 37min.

When is the sunrise / sunset in May in Boston?

On the first day of May in Boston, Massachusetts, sunrise is at 5:38 am and sunset at 7:43 pm. On the last day of the month, sunrise is at 5:10 am and sunset at 8:13 pm EDT.

How many hours of sunshine does Boston have in May?

In May, the average sunshine duration in Boston is 8.3h.

How high is the UV index in May in Boston?

In May, the average daily maximum UV index in Boston, Massachusetts, is 5. A UV Index of 3 to 5 symbolizes a medium hazard to health from exposure to the Sun's UV radiation.

Average temperature in May
Boston, MA

Average temperature in May - Boston, MA
  • Average high temperature in May: 66.4°F

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (34.2°F).

  • Average low temperature in May: 50°F

The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).

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Average pressure in May
Boston, MA

Average pressure in May - Boston, MA
  • Average pressure in May: 30.01"

The month with the highest atmospheric pressure is November (30.06").
The month with the lowest atmospheric pressure is June (29.93").

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Average wind speed in May
Boston, MA

Average wind speed in May - Boston, MA
  • Average wind speed in May: 7.4mph

The windiest month (with the highest average wind speed) is January (9.9mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).

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Average humidity in May
Boston, MA

Average humidity in May - Boston, MA
  • Average humidity in May: 72%

The month with the highest relative humidity is February (77%).
The month with the lowest relative humidity is April (69%).

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Average rainfall in May
Boston, MA

Average rainfall in May - Boston, MA
  • Average rainfall in May: 1.81"

The wettest months (with the highest rainfall) are March, April and December (2.91").
The driest month (with the least rainfall) is September (1.26").

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Average rainfall days in May
Boston, MA

Average rainfall days in May - Boston, MA
  • 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 January (7.9 days).

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Average snowfall in May
Boston, MA

Average snowfall in May - Boston, MA
  • Average snowfall in May: 0.04"

The month with the highest snowfall is February (4.72").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in May
Boston, MA

Average snowfall days in May - Boston, MA
  • Average snowfall days in May: 0.1 days

The months with the highest number of snowfall days are January and February (7.6 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in May
Boston, MA

Average sea temperature in May - Boston, MA
  • Average sea temperature in May: 49.2°F

The best month for swimming (with the highest average sea temperature) is August (67.9°F).
The coldest month (with the lowest average sea temperature) is February (38.1°F).

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Average daylight in May /
Average sunshine in May
Boston, MA

Average daylight in May / Average sunshine in May - Boston, MA
  • Average daylight in May: 14h and 37min

The month with the longest days is June (Average daylight: 15h and 14min).
The month with the shortest days is December (Average daylight: 9h and 8min).

  • Average sunshine in May: 8.3h

The month with the most sunshine is August (Average sunshine: 10.5h).
The month with the least sunshine is February (Average sunshine: 4.6h).

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Average sunshine days in May
Boston, MA

Average sunshine days in May - Boston, MA
  • Average sunshine days in May: 14.2 days

The month with the most sunshine days is September (17.7 days).
The month with the least sunshine days is April (13 days).

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Average UV index in May
Boston, MA

Average UV index in May - Boston, MA
  • Average UV index in May: 5

The months with the highest UV index are June, July and August (UV index 6).
The 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
Boston, MA

Average cloud cover in May - Boston, MA
  • Average cloud cover in May: 46

The month with the most cloud cover is March (Cloud cover 51).
The month with the least cloud cover is August (Cloud cover 32).

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Average visibility in May
Boston, MA

Average visibility in May - Boston, MA
  • 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).

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