Weather in September
Temperature
The transition into September in Isle Royale National Park indicates a reduction in the average high-temperature, down to an enjoyable 62.6°F (17°C) from August's pleasant 71.6°F (22°C). Isle Royale National Park experiences a mean low-temperature of 44.6°F (7°C) during September.Rainfall
September is the month with the most rainfall in Isle Royale National Park. Rain falls for 13 days and accumulates 3.39" (86mm) of precipitation.Ocean temperature
In September, the average ocean temperature in Isle Royale National Park is 53.6°F (12°C).Note: Swimming in 53.6°F (12°C) feels unbearing at 55.4°F (13°C) and can be life-risking below 50°F (10°C), causing breathing issues and cold shock, depending on a person's capacity.
Daylight
In Isle Royale National Park, the average length of the day in September is 12h and 34min.On the first day of the month, sunrise is at 7:14 am and sunset at 8:36 pm. On the last day of September, in Isle Royale National Park, sunrise is at 7:54 am and sunset at 7:36 pm EDT.
Sunshine
The average sunshine in September is 6h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: In September, an average UV index of 5 transforms into the following instructions:
Put precautions into practice - Guidance to elude sunburn is provided. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Isle Royale National Park in September?
What is the rainiest month in Isle Royale National Park?
How many days does it rain in September in Isle Royale National Park?
What is the water temperature in September in Isle Royale National Park?
How many hours of daylight does Isle Royale National Park have in September?
What time are sunrise and sunset in September in Isle Royale National Park?
How long on average sun shines in September in Isle Royale National Park?
What is the UV index reading in September in Isle Royale National Park?
Average temperature in September
Isle Royale National Park, MI
- Average high temperature in September: 63°F
The warmest month (with the highest average high temperature) is July (75°F).
The month with the lowest average high temperature is January (18°F).
- Average low temperature in September: 45°F
The month with the highest average low temperature is July (54°F).
The coldest month (with the lowest average low temperature) is January (0°F).
Average rainfall in September
Isle Royale National Park, MI
- Average rainfall in September: 3.4"
The wettest month (with the highest rainfall) is September (3.4").
The driest month (with the least rainfall) is February (1.5").
Average rainfall days in September
Isle Royale National Park, MI
- Average rainfall days in September: 13 days
The months with the highest number of rainy days are June and September (13 days).
The months with the least rainy days are February and April (8 days).
Average sea temperature in September
Isle Royale National Park, MI
- Average sea temperature in September: 54°F
The best month for swimming (with the highest average sea temperature) is August (55°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (36°F).
Average daylight in September /
Average sunshine in September
Isle Royale National Park, MI
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 6h
The month with the most sunshine is July (Average sunshine: 10h).
The months with the least sunshine are November and December (Average sunshine: 3h).
Average UV index in September
Isle Royale National Park, MI
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 1).
Isle Royale National Park, Michigan, USA
Weather forecast for your location
2. Allow the app to use your location