Duluth weather in September 2025

Expect 66°F daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in Duluth in September. Check more long-term weather averages for Duluth in September before you book your next holiday to Minnesota in 2025/2026.

  • 66°F maximum daytime temperature in September in Duluth66
    66°F max day temperature
  • 7 hours of sunshine per day
  • 12 days with some rainfall in September in Duluth12
    12 days with some rainfall
  • 46°F minimum night-time temperature in September in Duluth46
    46°F min night temperature
  • 13 hours of daylight per day in September in Duluth13
    13 hours of daylight per day
  • No heat & humidity in September in Duluth0
    No heat & humidity
  • 3.8 inches monthly rainfall in September in Duluth3.8
    3.8 inches of monthly rainfall
  • UV (maximum) index 5 (Moderate) in September in Duluth5
    5 (Moderate) UV index
  • 57°F sea temperature in September in Duluth57
    57°F sea temperature

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The September weather guide for Minnesota (Duluth) 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 Duluth in September?

Daytime temperatures usually reach 66°F in Duluth in September, falling to 46°F at night.

How sunny is it in Duluth in September?

There are normally 7 hours of bright sunshine each day in Duluth in September - that's 52% of daylight hours.

How warm is the sea around Duluth in September?

The average sea temperature around Duluth in September is 57°F.

Does it rain in Duluth in September?

There are usually 12 days with some rain in Duluth in September and the average monthly rainfall is 3.8 inches.

Duluth September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:29 18:47
Monday, 15th September 2025 05:47 18:19
Tuesday, 30th September 2025 06:06 17:49

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