Monthly weather forecast and climate
Groton, CT

Weather in January

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

Weather in February

February, the last month of the winter, in Groton, is another cold month, with average temperature fluctuating between 27°F (-2.8°C) and 37.9°F (3.3°C). In Groton, the average high-temperature in February is almost 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 temperature in the range of an average low of 32.9°F (0.5°C) and an average high of 43.3°F (6.3°C). In March, the average high-temperature marginally rises, from a cold 37.9°F (3.3°C) in February, to a chilly 43.3°F (6.3°C). Weather in March »

Weather in April

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

Weather in May

The last month of the spring, May, is a comfortable month in Groton, Connecticut, with average temperature ranging between max 63.3°F (17.4°C) and min 50.9°F (10.5°C). In May, the average high-temperature increases, from a fresh 53.4°F (11.9°C) in April, to a comfortable 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 temperature in the range of an average high of 71.4°F (21.9°C) and an average low of 59°F (15°C). In Groton, the average high-temperature slightly increases, 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 is a warm summer month in Groton, Connecticut, with average temperature fluctuating between 66.7°F (19.3°C) and 78.6°F (25.9°C). The warmest month is July, with an average high-temperature of 78.6°F (25.9°C) and an average low-temperature of 66.7°F (19.3°C). Weather in July »

Weather in August

August, the last month of the summer, in Groton, is another warm month, with average temperature fluctuating between 66.2°F (19°C) and 77.7°F (25.4°C). In August, the average high-temperature is almost 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 also an agreeable month in Groton, Connecticut, with average temperature ranging between max 72°F (22.2°C) and min 59.9°F (15.5°C). In Groton, Connecticut, the average high-temperature slightly decreases, 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 enjoyable autumn month, with average temperature varying between 61.7°F (16.5°C) and 50.9°F (10.5°C). In Groton, the average high-temperature drops, from an agreeable 72°F (22.2°C) in September, to an enjoyable 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 average temperature fluctuating between 50.9°F (10.5°C) and 40.6°F (4.8°C). In November, the average high-temperature decreases, 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 average temperature fluctuating between 41.9°F (5.5°C) and 33.3°F (0.7°C). In December, the average high-temperature decreases, from a cool 50.9°F (10.5°C) in November, to a cold 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, 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?

Months with the lowest humidity in Groton, Connecticut, are January, March, April and November, with an average relative humidity of 74%.

How much does it rain in Groton?

In Groton, Connecticut, during the entire year, the rain falls for 159.8 days and collects up to 33.07" (840mm) of precipitation.

When does it snow in Groton?

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

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?

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

What month is the ocean coldest in Groton?

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

What is the month with the least sunshine in Groton?

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

What is the snowiest month in Groton?

The month with the most snowfall in Groton is March when snow falls for 5.1 days and typically aggregates up to 2.56" (65mm) of snow.

When it does not snow in Groton?

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

What is the most humid month in Groton?

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

When are the longest days in Groton?

The month with the longest days is June, with an average of 15.1h of daylight.

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

Months with the highest UV index in Groton, Connecticut, are June through August, with an average maximum UV index of 6.

What is the warmest month in Groton?

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

What month is the ocean warmest in Groton?

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

What month has the most sunshine in Groton?

August has the most sunshine of the year, 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, Connecticut. Rain falls for 12 days and accumulates 1.65" (42mm) of precipitation.

What is the wettest month in Groton?

December is the month with the most rainfall in Groton. Rain falls for 13.4 days and accumulates 3.86" (98mm) of precipitation.

What is the month with the shortest days in Groton?

The month with the shortest days is December, with an average of 9.2h 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").
The month with the lowest atmospheric pressure is June (29.93").

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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%).
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").
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).
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: 15.1h).
The month with the shortest days is December (Average daylight: 9.2h).

The month with the most sunshine is August (Average sunshine: 10.6h).
Months with the least sunshine are February and December (Average sunshine: 4.9).

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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

Months with the highest UV index are June, July and August (UV index 6).
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

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

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