Grand Portage weather in September 2025

Expect 18°C daytime maximum temperatures in the shade with on average 6 hours of sunshine per day in Grand Portage in September. Check more long-term weather averages for Grand Portage in September before you book your next holiday to Minnesota in 2025/2026.

  • 18°C maximum daytime temperature in September in Grand Portage18
    18°C max day temperature
  • 6 hours of sunshine per day
  • 12 days with some rainfall in September in Grand Portage12
    12 days with some rainfall
  • 5°C minimum night-time temperature in September in Grand Portage5
    5°C min night temperature
  • 13 hours of daylight per day in September in Grand Portage13
    13 hours of daylight per day
  • No heat & humidity in September in Grand Portage0
    No heat & humidity
  • 88 mm monthly rainfall in September in Grand Portage88
    88 mm of monthly rainfall
  • UV (maximum) index 5 (Moderate) in September in Grand Portage5
    5 (Moderate) UV index
  • 13°C sea temperature in September in Grand Portage13
    13°C sea temperature

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The September weather guide for Minnesota (Grand Portage) 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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How hot is it in Grand Portage in September?

Daytime temperatures usually reach 18°C in Grand Portage in September, falling to 5°C at night.

How sunny is it in Grand Portage in September?

There are normally 6 hours of bright sunshine each day in Grand Portage in September - that's 45% of daylight hours.

How warm is the sea around Grand Portage in September?

The average sea temperature around Grand Portage in September is 13°C.

Does it rain in Grand Portage in September?

There are usually 12 days with some rain in Grand Portage in September and the average monthly rainfall is 88mm.

Grand Portage September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:17 18:39
Monday, 15th September 2025 05:36 18:10
Tuesday, 30th September 2025 05:57 17:39

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