New Haven weather in September 2025

Q: 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.

Q: 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.

Q: How warm is the sea around New Haven in September?

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

Q: 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.

Q: What is the chance of a cyclone 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.

Expect 73°F 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.

73
73°F max day temperature
7
7 hours of sunshine per day
8
8 days with some rainfall
55
55°F min night temperature
12
12 hours of daylight per day
0
No heat & humidity
3.3
3.3 inches of monthly rainfall
6
6 (High) UV index
70
70°F 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) | Imperial (°F)

More about the USA

How hot is it in New Haven in September?

Daytime temperatures usually reach 73°F in New Haven in September, falling to 55°F 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 70°F.

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 3.3 inches.

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.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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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Connecticut - quick facts
Flight time^✝	10.5 hours
Time difference	UK -5 hours
Language(s)	English
Currency	US Dollar
Electricity	A + B plug (120V)
Driving side	Right
Visa^✝	Yes
Tourist info	Connecticut Office of Tourism