Climate and monthly weather forecast
Groton, CT

Weather in January

January, the same as December, is a wintry winter month in Groton, Connecticut, with an average temperature fluctuating between 26.2°F (-3.2°C) and 36.1°F (2.3°C). With an average high-temperature of 36.1°F (2.3°C) and an average low-temperature of 26.2°F (-3.2°C), January is the coldest month. Weather in January »

Weather in February

February, the last month of the winter in Groton, is another cold month, with an average temperature ranging between min 27°F (-2.8°C) and max 37.9°F (3.3°C). In Groton, Connecticut, the average high-temperature in February is relatively the same as in January - a still wintry 37.9°F (3.3°C). Weather in February »

Weather in March

The first month of the spring, March, is a chilly month in Groton, Connecticut, with an average temperature fluctuating between 32.9°F (0.5°C) and 43.3°F (6.3°C). In March, the average high-temperature slightly increases from a wintry 37.9°F (3.3°C) in February to a chilly 43.3°F (6.3°C). Weather in March »

Weather in April

April is a fresh spring month in Groton, Connecticut, with an average temperature varying between 42.4°F (5.8°C) and 53.4°F (11.9°C). In April, the average high-temperature increases from a frosty 43.3°F (6.3°C) in March to a cool 53.4°F (11.9°C). Weather in April »

Weather in May

May, the last month of the spring in Groton, is a comfortable month, with an average temperature fluctuating between 50.9°F (10.5°C) and 63.3°F (17.4°C). In May, the average high-temperature rises from a fresh 53.4°F (11.9°C) in April to an enjoyable 63.3°F (17.4°C). Weather in May »

Weather in June

The first month of the summer, June, is an agreeable month in Groton, Connecticut, with an average temperature ranging between max 71.4°F (21.9°C) and min 59°F (15°C). In June, the average high-temperature marginally rises from a comfortable 63.3°F (17.4°C) in May to an agreeable 71.4°F (21.9°C). Weather in June »

Weather in July

July in Groton, Connecticut, is a warm summer month, with an average temperature fluctuating between 66.7°F (19.3°C) and 78.6°F (25.9°C). With an average high-temperature of 78.6°F (25.9°C) and an average low-temperature of 66.7°F (19.3°C), July is the warmest month. Weather in July »

Weather in August

The last month of the summer, August, is another warm month in Groton, Connecticut, with an average temperature fluctuating between 77.7°F (25.4°C) and 66.2°F (19°C). In Groton, the average high-temperature in August is relatively the same as in July - a still warm 77.7°F (25.4°C). Weather in August »

Weather in September

The first month of the autumn, September, is still a pleasant month in Groton, Connecticut, with an average temperature varying between 59.9°F (15.5°C) and 72°F (22.2°C). In September, the average high-temperature marginally drops from a moderately hot 77.7°F (25.4°C) in August to an agreeable 72°F (22.2°C). Weather in September »

Weather in October

October, like September, in Groton, Connecticut, is another comfortable autumn month, with temperature in the range of an average low of 50.9°F (10.5°C) and an average high of 61.7°F (16.5°C). In October, the average high-temperature decreases from a pleasant 72°F (22.2°C) in September to a comfortable 61.7°F (16.5°C). Weather in October »

Weather in November

The last month of the autumn, November, is another cool month in Groton, Connecticut, with temperature in the range of an average high of 50.9°F (10.5°C) and an average low of 40.6°F (4.8°C). In Groton, Connecticut, the average high-temperature in November drops from an enjoyable 61.7°F (16.5°C) in October to a cool 50.9°F (10.5°C). Weather in November »

Weather in December

December, the first month of the winter in Groton, is also a wintry month, with an average temperature fluctuating between 33.3°F (0.7°C) and 41.9°F (5.5°C). In December, the average high-temperature decreases from a fresh 50.9°F (10.5°C) in November to a wintry 41.9°F (5.5°C). Weather in December »
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FAQ

What is the coldest month in Groton?

January is the coldest month in Groton, with an average high-temperature of 36.1°F (2.3°C) and an average low-temperature of 26.2°F (-3.2°C).

What is the least humid month in Groton?

January, March, April and November, with an average relative humidity of 74%, are the least humid months.

How much does it rain in Groton?

Throughout the year, in Groton, there are 159.8 rainfall days, and 33.07" (840mm) of precipitation is accumulated.

When does it snow in Groton?

January through April, November and December are months with snowfall.

How much does it snow in Groton?

Throughout the year, there are 24 snowfall days, and 7.68" (195mm) of snow is accumulated.

What is the month with the lowest UV index in Groton?

The months with the lowest UV index in Groton are January through March, November and December, with an average maximum UV index of 2.

What is the month with the coldest ocean in Groton?

February is the month with the coldest seawater, with an average ocean temperature of 38.8°F (3.8°C).

What is the month with the least sunshine in Groton?

February and December, with an average of 4.9h of sunshine, are months with the least sunshine.

When does it snow the most in Groton?

March is the month with the most snowfall in Groton, Connecticut. Snow falls for 5.1 days and accumulates 2.56" (65mm) of snow.

When is Daylight Saving Time (DST) in Groton?

On Sunday, March 13. 2022, at 2:00 am, Daylight Saving Time starts in Groton, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 6. 2022, at 2:00 am, and the time zone reverts from EDT to EST.

When it does not snow in Groton?

In Groton, snow does not fall in May through October.

What is the most humid month in Groton?

The most humid month in Groton is June, with an average relative humidity of 80%.

When are the longest days in Groton?

June has the longest days of the year, with an average of 15h and 7min of daylight.

What is the month with the highest UV index in Groton?

June through August, with an average maximum UV index of 6, are months with the highest UV index.

What is the warmest month in Groton?

July is the warmest month, with an average high-temperature of 78.6°F (25.9°C) and an average low-temperature of 66.7°F (19.3°C).

When is the ocean warmest in Groton?

With an average ocean temperature of 72.1°F (22.3°C), August is the month with the warmest seawater in Groton.

What month has the most sunshine in Groton?

The month with the most sunshine in Groton is August, with an average of 10.6h of sunshine.

What is the driest month in Groton?

September is the month with the least rainfall in Groton. Rain falls for 12 days and accumulates 1.65" (42mm) of precipitation.

What is the wettest month in Groton?

The month with the most rainfall in Groton is December, when the rain falls for 13.4 days and typically aggregates up to 3.86" (98mm) of precipitation.

What is the month with the shortest days in Groton?

The month with the shortest days in Groton is December, with an average of 9h and 15min of daylight.

Average temperature
Groton, CT

Average temperature - Groton, CT

The warmest month (with the highest average high temperature) is July (78.6°F).
The month with the lowest average high temperature is January (36.1°F).

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).

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Average pressure
Groton, CT

Average pressure - Groton, CT

The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed
Groton, CT

Average wind speed - Groton, CT

The windiest month (with the highest average wind speed) is January (11.9mph).
The calmest months (with the lowest average wind speed) are July and August (7.8mph).

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Average humidity
Groton, CT

Average humidity - Groton, CT

The month with the highest relative humidity is June (80%).
The months with the lowest relative humidity are January, March, April and November (74%).

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Average rainfall
Groton, CT

Average rainfall - Groton, CT

The wettest month (with the highest rainfall) is December (3.86").
The driest month (with the least rainfall) is September (1.65").

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Average rainfall days
Groton, CT

Average rainfall days - Groton, CT

The month with the highest number of rainy days is July (15.8 days).
The month with the least rainy days is February (9.5 days).

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Average snowfall
Groton, CT

Average snowfall - Groton, CT

The month with the highest snowfall is March (2.56").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days
Groton, CT

Average snowfall days - Groton, CT

The month with the highest number of snowfall days is February (6.8 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

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Average sea temperature
Groton, CT

Average sea temperature - Groton, CT

The best month for swimming (with the highest average sea temperature) is August (72.1°F).
The coldest month (with the lowest average sea temperature) is February (38.8°F).

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Average daylight / Average sunshine
Groton, CT

Average daylight / Average sunshine - Groton, CT

The month with the longest days is June (Average daylight: 15h and 7min).
The month with the shortest days is December (Average daylight: 9h and 15min).

The month with the most sunshine is August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 54min).

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Average sunshine days
Groton, CT

Average sunshine days - Groton, CT

The month with the most sunshine days is November (16.5 days).
The month with the least sunshine days is February (12.5 days).

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Average UV index
Groton, CT

Average UV index - Groton, CT

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 visibility
Groton, CT

Average visibility - Groton, CT

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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