Cos Cob Weather in December

What's the weather like in Cos Cob (Connecticut) in December 2025?

The climate in Cos Cob during December can be summarized as cold and damp.

December is in the winter in Cos Cob and is typically the 3rd coldest month of the year. Daytime maximum temperatures average around a cold 5°C (41°F), whilst at night -5°C (23°F) is normal.

Cos Cob weather averages (imperial / metric)
Daytime temperature 4.9°C 40.8°F
Nightly temperature -4.9°C 23.2°F
Average temperature 0°C 32°F
Daily sunshine 5 hrs
Avg rainfall 115 mm 4.5 ins
Rainy days 12 days
Sea temperature 9°C 48.2°F
Humidity 68%
Windspeed 19.8kph 12 mph

On average December is the 6th wettest month of the year in Cos Cob with around 115mm 4.5 inches of rain making it a damp time to visit. This rainfall is typically spread over 12 days, although this may vary considerably.

On the flip side this corresponds to an average of 5 hours of sunshine per day.

December temperatures in Cos Cob

Cos Cob average temperature in December

December rainfall

Cos Cob average rain in December

December hourly sunshine

Cos Cob average rain in December

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Cos Cob in December 2025.

Other monthly averages

Best places to visit in December

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Cos Cob weather stats

Cos Cob weather statistics
Hottest month: July 28.4°C 83.1°F
Driest month: February 90mm 3.5ins
Sunniest month: August 9.1hrs
Coldest month: January 2.3°C 36.1°F
Wettest month: May 126mm 5ins
Map showing location of Cos Cob (41.03343, -73.59957) Cos Cob map pin © Google

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