September weather forecastDuluth, MN
September
Weather in September
September acts as a harbinger of autumn in Duluth, minor reductions in temperature, daylight hours, and sea temperature distinguish this month. This period is characterized by frequent weather changes and an upsurge in rainfall. The city also witnesses a reduction in pressure levels, indicative of the changing seasons. Despite this shift, the number of sunshine hours remains generous, promising ample daylight. The average high temperature continues its descent, registering at 67.1°F (19.5°C).Temperature
Start of September brings a slight shift in the average high-temperature, dipping a bit from August's warm 75.7°F (24.3°C) to a refreshing 67.1°F (19.5°C). Throughout September, an average low-temperature of 49.1°F (9.5°C) is expected.Humidity
The average relative humidity in September is 78%.Rainfall
In Duluth, in September, during 13.6 rainfall days, 2.05" (52mm) of precipitation is typically accumulated. In Duluth, during the entire year, the rain falls for 135.2 days and collects up to 24.53" (623mm) of precipitation.Snowfall
June through September are months without snowfall.Ocean temperature
In Duluth, in September, the average water temperature is 57.2°F (14°C).Note: Dipping into 57.2°F (14°C) below 50°F (10°C) needs protective wear, or you'd face cold shock and breathing issues swiftly. Meanwhile, a slight swim around 55.4°F (13°C) feels cold to the bone.
Daylight
In Duluth, the average length of the day in September is 12h and 32min.On the first day of September in Duluth, Minnesota, sunrise is at 6:29 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:06 am and sunset at 6:49 pm CDT.
Sunshine
In September, the average sunshine is 8.3h.UV index
The average daily maximum UV index in September in Duluth is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: An average UV index of 4 in September transforms into this advice:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Duluth, MN
- Average high temperature in September: 67.1°F
The warmest month (with the highest average high temperature) is July (77.4°F).
The month with the lowest average high temperature is January (16.3°F).
- Average low temperature in September: 49.1°F
The month with the highest average low temperature is July (57.6°F).
The coldest month (with the lowest average low temperature) is January (3.9°F).
Average pressure in September
Duluth, MN
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is February (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Duluth, MN
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is April (8.8mph).
The calmest months (with the lowest average wind speed) are July and August (6.6mph).
Average humidity in September
Duluth, MN
- Average humidity in September: 78%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is May (72%).
Average rainfall in September
Duluth, MN
- Average rainfall in September: 2.05"
The wettest month (with the highest rainfall) is July (3.03").
The driest month (with the least rainfall) is January (0.87").
Average rainfall days in September
Duluth, MN
- Average rainfall days in September: 13.6 days
The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in September
Duluth, MN
- Average snowfall in September: 0"
The month with the highest snowfall is December (7.72").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Duluth, MN
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (20.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Duluth, MN
- Average sea temperature in September: 57°F
The best month for swimming (with the highest average sea temperature) is August (61°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
Duluth, MN
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 8h and 18min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 2h and 48min).
Average sunshine days in September
Duluth, MN
- Average sunshine days in September: 13.2 days
The month with the most sunshine days is November (13.7 days).
The month with the least sunshine days is June (10.1 days).
Average UV index in September
Duluth, MN
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Duluth, MN
- Average cloud cover in September: 40
The month with the most cloud cover is January (Cloud cover 72).
The month with the least cloud cover is July (Cloud cover 34).
Average visibility in September
Duluth, MN
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
