Mystic weather in December 2025

Expect daytime maximum temperatures of 41°F in Mystic, Connecticut in December based on long-term weather averages. There are 5 hours of sunshine per day on average with 12 days with some rainfall and typically 4.6 inches of rainfall in the month, which might fall as snow.

  • 41°F maximum daytime temperature in December in Mystic41
    41°F max day temperature
  • 5 hours of sunshine per day
  • 12 days with some rainfall in December in Mystic12
    12 days with some rainfall
  • 25°F minimum night-time temperature in December in Mystic25
    25°F min night temperature
  • 9 hours of daylight per day in December in Mystic9
    9 hours of daylight per day
  • No heat & humidity in December in Mystic0
    No heat & humidity
  • 4.6 inches monthly rainfall in December in Mystic4.6
    4.6 inches of monthly rainfall
  • UV (maximum) index 1 (Low) in December in Mystic1
    1 (Low) UV index
  • 46°F sea temperature in December in Mystic46
    46°F sea temperature

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The December weather guide for Connecticut (Mystic) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C)  |  Imperial (°F)

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How cold is it in Mystic in December?

Daytime temperatures usually reach 41°F in Mystic in December, falling to 25°F at night.

How sunny is it in Mystic in December?

There are normally 5 hours of bright sunshine each day in Mystic in December - that's 51% of daylight hours.

How warm is the sea around Mystic in December?

The average sea temperature around Mystic in December is 46°F.

Does it rain in Mystic in December?

There are usually 12 days with some rain in Mystic in December and the average monthly rainfall is 4.6 inches. Rain may fall as snow in this month.

Mystic December sunrise & sunset times

Browse the sunrise and sunset times for Mystic in December 2025. Select a month to view Mystic sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st December 2025 06:55 16:19
Tuesday, 16th December 2025 07:08 16:20
Wednesday, 31st December 2025 07:14 16:28

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