September weather forecastAlpena, MI
September
Weather in September
A subtle climatic shift towards fall materializes in Alpena during September. The rising wind speed and declining temperature to 67.1°F (19.5°C) denote the onset of autumn. The dwindling daylight hours usher in increasingly cooler days, while the sea temperature gradually subsides. September's weather in Alpena witnesses a steady progression from summer's warmth towards fall's crisp ambiance. This period sees a balanced amalgamation of warmth, wind speed, and humidity.Temperature
The start of September signals a gentle decrease in the average high-temperature, transitioning from a moderately hot 73.9°F (23.3°C) in August to a comfortable 67.1°F (19.5°C). Throughout September, Alpena witnesses a nighttime temperature average of 54.3°F (12.4°C).Humidity
In Alpena, the average relative humidity in September is 77%.Rainfall
In Alpena, in September, during 11.3 rainfall days, 0.98" (25mm) of precipitation is typically accumulated. Throughout the year, there are 119.4 rainfall days, and 13.9" (353mm) of precipitation is accumulated.Snowfall
In Alpena, snow does not fall in June through September.Ocean temperature
In Alpena, in September, the average water temperature is 60.8°F (16°C).Note: Swimming in water at 60.8°F (16°C) is not a pleasurable experience for most. The task of managing breathing becomes more challenging as the water temperature descends from 69.8°F (21°C) to 59°F (15°C).
Daylight
In Alpena, the average length of the day in September is 12h and 31min.On the first day of September, sunrise is at 6:56 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 7:31 am and sunset at 7:15 pm EDT.
Sunshine
In September, the average sunshine in Alpena is 8h.UV index
In Alpena, Michigan, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: A daily high UV index of 3 in September leads to these guidelines:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Alpena, MI
- Average high temperature in September: 67.1°F
The warmest month (with the highest average high temperature) is July (74.1°F).
The month with the lowest average high temperature is January (25.9°F).
- Average low temperature in September: 54.3°F
The month with the highest average low temperature is August (60.3°F).
The coldest months (with the lowest average low temperature) are January and February (18°F).
Average pressure in September
Alpena, MI
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is March (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Alpena, MI
- Average wind speed in September: 8.7mph
The windiest months (with the highest average wind speed) are January and December (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.5mph).
Average humidity in September
Alpena, MI
- Average humidity in September: 77%
The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is May (73%).
Average rainfall in September
Alpena, MI
- Average rainfall in September: 0.98"
The wettest month (with the highest rainfall) is May (1.61").
The driest month (with the least rainfall) is February (0.71").
Average rainfall days in September
Alpena, MI
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is October (14.3 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Alpena, MI
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.58").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Alpena, MI
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (20.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Alpena, MI
- Average sea temperature in September: 61°F
The best month for swimming (with the highest average sea temperature) is August (64°F).
The coldest months (with the lowest average sea temperature) are February, March and April (36°F).
Average daylight in September /
Average sunshine in September
Alpena, MI
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 8h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 1h and 48min).
Average sunshine days in September
Alpena, MI
- Average sunshine days in September: 15.5 days
The month with the most sunshine days is May (17.8 days).
The month with the least sunshine days is January (8.4 days).
Average UV index in September
Alpena, MI
- Average UV index in September: 3
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Alpena, MI
- Average cloud cover in September: 35
The month with the most cloud cover is January (Cloud cover 80).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in September
Alpena, MI
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
