Mystic weather in September 2025

Expect 72°F daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in Mystic in September. Check more long-term weather averages for Mystic in September before you book your next holiday to Connecticut in 2025/2026.

  • 72°F maximum daytime temperature in September in Mystic72
    72°F max day temperature
  • 8 hours of sunshine per day
  • 8 days with some rainfall in September in Mystic8
    8 days with some rainfall
  • 54°F minimum night-time temperature in September in Mystic54
    54°F min night temperature
  • 12 hours of daylight per day in September in Mystic12
    12 hours of daylight per day
  • No heat & humidity in September in Mystic0
    No heat & humidity
  • 3.8 inches monthly rainfall in September in Mystic3.8
    3.8 inches of monthly rainfall
  • UV (maximum) index 6 (High) in September in Mystic6
    6 (High) UV index
  • 66°F sea temperature in September in Mystic66
    66°F sea temperature

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The September 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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More about the USA

How hot is it in Mystic in September?

Daytime temperatures usually reach 72°F in Mystic in September, falling to 54°F at night.

How sunny is it in Mystic in September?

There are normally 8 hours of bright sunshine each day in Mystic in September - that's 60% of daylight hours.

How warm is the sea around Mystic in September?

The average sea temperature around Mystic in September is 66°F.

Does it rain in Mystic in September?

There are usually 8 days with some rain in Mystic in September and the average monthly rainfall is 3.8 inches.

What is the chance of a hurricane in Mystic in September?

On average less than 1 day in September in Mystic is likely to be affected by the passage of one or more tropical storms.

Mystic September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:14 18:20
Monday, 15th September 2025 05:29 17:57
Tuesday, 30th September 2025 05:44 17:31

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