New Haven weather in September 2025

Expect 23°C daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in New Haven in September. Check more long-term weather averages for New Haven in September before you book your next holiday to Connecticut in 2025/2026.

  • 23°C maximum daytime temperature in September in New Haven23
    23°C max day temperature
  • 7 hours of sunshine per day
  • 8 days with some rainfall in September in New Haven8
    8 days with some rainfall
  • 13°C minimum night-time temperature in September in New Haven13
    13°C min night temperature
  • 12 hours of daylight per day in September in New Haven12
    12 hours of daylight per day
  • No heat & humidity in September in New Haven0
    No heat & humidity
  • 85 mm monthly rainfall in September in New Haven85
    85 mm of monthly rainfall
  • UV (maximum) index 6 (High) in September in New Haven6
    6 (High) UV index
  • 21°C sea temperature in September in New Haven21
    21°C sea temperature

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The September weather guide for Connecticut (New Haven) 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 / mm)  |  Imperial (°F / inches)

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More about the USA

How hot is it in New Haven in September?

Daytime temperatures usually reach 23°C in New Haven in September, falling to 13°C at night.

How sunny is it in New Haven in September?

There are normally 7 hours of bright sunshine each day in New Haven in September - that's 60% of daylight hours.

How warm is the sea around New Haven in September?

The average sea temperature around New Haven in September is 21°C.

Does it rain in New Haven in September?

There are usually 8 days with some rain in New Haven in September and the average monthly rainfall is 85mm.

What is the chance of a hurricane in New Haven in September?

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

New Haven September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:18 18:24
Monday, 15th September 2025 05:32 18:00
Tuesday, 30th September 2025 05:48 17:35

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