nomadseason

Monthly climate in Groton, Connecticut, United States

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Groton features a oceanic climate (Cfb).Temperatures typically range between 2 °C (35 °F) and 22 °C (73 °F) through the year, but rarely can drop to -16 °C (4 °F) or can rise to as high as 29 °C (85 °F).The average annual precipitation amounts to about 1367 mm (53.8 inches) and receives 124 rainy days on the 1 mm (0.04 inches) threshold annually.Groton enjoys an average of 3053 hours of sunshine throughout the year, and daylight varies from 9 hours 13 minutes to 15 hours 5 minutes per day.

Monthly average temperatures in Groton, Connecticut, United States §

The warmest months in Groton are July, August and September, with daily mean temperatures ranging from 20 to 22 °C (68 - 73 °F) throughout the day. The coldest temperatures usually occur in January, February and March, when daily mean temperatures range from 2 to 4 °C (35 - 39 °F) throughout the day. On average each year, Groton experiences 13 days above 25 °C (77.0 °F) and 49 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Groton, Connecticut, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 14°C
(58°F)		 12°C
(54°F)		 15°C
(60°F)		 18°C
(65°F)		 22°C
(72°F)		 25°C
(78°F)		 29°C
(85°F)		 28°C
(83°F)		 27°C
(82°F)		 25°C
(77°F)		 20°C
(68°F)		 16°C
(61°F)
Mean maximum 11°C
(53°F)		 11°C
(51°F)		 12°C
(54°F)		 15°C
(58°F)		 20°C
(69°F)		 24°C
(76°F)		 28°C
(82°F)		 27°C
(81°F)		 25°C
(78°F)		 23°C
(73°F)		 18°C
(66°F)		 15°C
(59°F)
Average high 4°C
(40°F)		 5°C
(41°F)		 6°C
(44°F)		 10°C
(51°F)		 15°C
(59°F)		 20°C
(68°F)		 24°C
(75°F)		 24°C
(76°F)		 22°C
(71°F)		 18°C
(64°F)		 12°C
(53°F)		 7°C
(44°F)
Daily mean 2°C
(35°F)		 2°C
(36°F)		 4°C
(39°F)		 8°C
(47°F)		 13°C
(55°F)		 18°C
(64°F)		 22°C
(72°F)		 22°C
(73°F)		 20°C
(68°F)		 16°C
(60°F)		 9°C
(49°F)		 4°C
(40°F)
Average low -1°C
(30°F)		 -0°C
(32°F)		 1°C
(35°F)		 6°C
(43°F)		 11°C
(51°F)		 16°C
(61°F)		 20°C
(69°F)		 21°C
(70°F)		 18°C
(64°F)		 13°C
(56°F)		 6°C
(44°F)		 2°C
(36°F)
Mean minimum -12°C
(11°F)		 -9°C
(16°F)		 -6°C
(21°F)		 2°C
(35°F)		 6°C
(43°F)		 12°C
(53°F)		 17°C
(63°F)		 17°C
(63°F)		 13°C
(55°F)		 6°C
(44°F)		 -3°C
(28°F)		 -6°C
(21°F)
Minimum -16°C
(4°F)		 -13°C
(9°F)		 -9°C
(16°F)		 -0°C
(32°F)		 3°C
(38°F)		 10°C
(50°F)		 15°C
(59°F)		 15°C
(60°F)		 10°C
(51°F)		 4°C
(39°F)		 -7°C
(20°F)		 -11°C
(12°F)

Compare climate in Groton with other places

Compare temperature, precipitation, sunshine, UV index in Groton, Connecticut, United States with other places around the world.

Monthly average precipitation in Groton, Connecticut, United States §

Groton usually has the most precipitation in April, October and December, with an average of 11 rainy days and 145 mm (5.7 inches) of precipitation per month.The driest months in Groton are January, June and September. On average, 89 mm (3.5 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Groton, Connecticut, United States.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 83 (3.3) 109 (4.3) 108 (4.3) 136 (5.3) 119 (4.7) 84 (3.3) 115 (4.5) 101 (4.0) 101 (4.0) 157 (6.2) 113 (4.4) 141 (5.6)
Average precipitation days (≥ 1 mm) 8 11 9 12 13 10 10 9 9 12 10 11

Monthly sunshine hours in Groton, Connecticut, United States §

The sunniest months in Groton are June, July and August, when the sun shines an average of 10 hours 56 minutes a day.Least sunny months in Groton: January, February and December receive an average of 5 hours 39 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Groton, Connecticut, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 152 186 262 253 294 324 351 331 281 232 207 175
Mean daily daylight hours 9h 33m 10h 37m 11h 58m 13h 21m 14h 31m 15h 5m 14h 46m 13h 44m 12h 25m 11h 2m 9h 50m 9h 13m

Solar UV radiation in Groton, Connecticut, United States §

Groton experiences the highest level of ultraviolet (UV) radiation in June, July and August, when the maximum UV index can reach values of 9 - 10, which corresponds to the Very High category of sun exposure.January, November and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 4. For more detailed information, check out our hourly Groton UV Index data.

Average daily maximum UV levels by month for Groton, Connecticut, United States.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 3 5 6 8 9 10 10 9 8 6 4 2