September weather forecast
Alpena, MI

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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.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature in Alpena?

The high-temperature, in September, in Alpena, records 67.1°F (19.5°C), while the low-temperature is 54.3°F (12.4°C).

What is the average humidity in September in Alpena?

In Alpena, the average relative humidity in September is 77%.

How much does it rain in Alpena in September?

In Alpena, Michigan, in September, during 11.3 rainfall days, 0.98" (25mm) of precipitation is typically accumulated.

When it does not snow in Alpena?

In Alpena, snow does not fall in June through September.

Does it snow in Alpena in September?

In Alpena, in September, it doesn't snow. In October, it regularly snows.

What is the ocean temperature in September in Alpena?

In September, the average ocean temperature in Alpena, Michigan, is 60.8°F (16°C). For most, swimming in 60.8°F (16°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

What is the average length of the day in September in Alpena?

In September, the average day length in Alpena is 12h and 31min.

When are sunrise and sunset in September in Alpena?

In September, on the first day of the month, sunrise is at 6:56 am and sunset at 8:10 pm. On the last day of the month, in Alpena, Michigan, sunrise is at 7:31 am and sunset at 7:15 pm EDT.

How many hours of sunshine does Alpena have in September?

In Alpena, Michigan, the average sunshine duration in September is 8h.

What is the UV index intensity in September in Alpena?

The average daily maximum UV index in September in Alpena is 3. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Alpena, MI

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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 / Average sunshine in September - Alpena, MI
  • Average daylight in September: 12h and 3min

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 - 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 - 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 - 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 - 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).

Alpena, Michigan, USA

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