September weather forecast
Petersburg, AK

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Colorful buildings, docked ships in Quaint fishing village in Petersburg, Alaska, on Mitkof Island
Colorful buildings, docked ships in Quaint fishing village in Petersburg, Alaska, on Mitkof Island

Weather in September

The change in seasons from summer to autumn becomes evident in September. Lower temperatures make a comeback, while rainfall is also partly prevalent, a telltale sign of the approaching winter. The days start to shorten, and cooler evenings usher in the mild autumnal charm. September brings about the first signs of snowfall, albeit minimal, at 0.31" (8mm). This month signals the transition into the winter months and lets citizens savor the quick passing of fall.

Temperature

September notes an average high-temperature of a cool 54.3°F (12.4°C), subtly differing from August's 59°F (15°C). Petersburg encounters an average temperature dip to a frosty 46.4°F (8°C) throughout September, subtly lower than its daytime maximum.

Humidity

In September, the average relative humidity is 84%.

Rainfall

In September, in Petersburg, the rain falls for 17.5 days. Throughout September, 5.12" (130mm) of precipitation is accumulated. Throughout the year, there are 197.9 rainfall days, and 53.03" (1347mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall.

Ocean temperature

In Petersburg, in September, the average water temperature is 52°F (11.1°C).
Note: In 52°F (11.1°C), even brief exposure to 55.4°F (13°C) feels biting, and anything less than 50°F (10°C) risks cold shock and impaired breathing, considering one's health.

Daylight

In September, the average length of the day in Petersburg, Alaska, is 12h and 44min.
On the first day of the month, sunrise is at 5:56 am and sunset at 7:46 pm. On the last day of September, in Petersburg, sunrise is at 6:55 am and sunset at 6:27 pm AKDT.

Sunshine

The average sunshine in September in Petersburg is 6.7h.

UV index

The average daily maximum UV index in September in Petersburg is 2. A UV Index of 2, and less, symbolizes a low health risk from exposure to the Sun's UV rays for the ordinary person.
Note: A maximum high daily UV index of 2 during September translates into the following directions:
Most individuals face no significant issues with extended sun exposure, but it is always essential to protect children, babies, and those with sensitive skin. It's recommended to limit sun exposure when its radiation is at its peak during midday. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
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Frequently asked questions

What are the temperatures in Petersburg in September?

In September, in Petersburg, the average high-temperature is 54.3°F (12.4°C), and the average low-temperature is 46.4°F (8°C).

What is the average humidity in September in Petersburg?

The average relative humidity in September in Petersburg is 84%.

How much does it rain in Petersburg in September?

In Petersburg, in September, during 17.5 rainfall days, 5.12" (130mm) of precipitation is typically accumulated.

When it does not snow in Petersburg?

In Petersburg, Alaska, snow does not fall in June through September.

Does it snow in Petersburg in September?

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

How cold is the water in September in Petersburg?

In September, the average ocean temperature in Petersburg is 52°F (11.1°C). Swimming in 52°F (11.1°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

How many hours of daylight does Petersburg have in September?

The average day length in September in Petersburg is 12h and 44min.

When is the sunrise / sunset in September in Petersburg?

On the first day of September in Petersburg, Alaska, sunrise is at 5:56 am and sunset at 7:46 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:27 pm AKDT.

How long on average sun shines in September in Petersburg?

The average sunshine duration in September in Petersburg is 6.7h.

What is the UV index intensity in September in Petersburg?

The average daily maximum UV index in September is 2. A UV Index reading of 2, and below, represents a low health risk 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
Petersburg, AK

Average temperature in September - Petersburg, AK
  • Average high temperature in September: 54.3°F

The warmest month (with the highest average high temperature) is July (59.7°F).
The month with the lowest average high temperature is December (32.4°F).

  • Average low temperature in September: 46.4°F

The month with the highest average low temperature is July (50.2°F).
The coldest month (with the lowest average low temperature) is February (25.9°F).

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Average pressure in September
Petersburg, AK

Average pressure in September - Petersburg, AK
  • Average pressure in September: 29.91"Hg

The month with the highest atmospheric pressure is July (30.05"Hg).
The month with the lowest atmospheric pressure is November (29.8"Hg).

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Average wind speed in September
Petersburg, AK

Average wind speed in September - Petersburg, AK
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is January (8.2mph).
The calmest month (with the lowest average wind speed) is July (3.9mph).

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Average humidity in September
Petersburg, AK

Average humidity in September - Petersburg, AK
  • Average humidity in September: 84%

The months with the highest relative humidity are January and August (86%).
The month with the lowest relative humidity is May (81%).

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Average rainfall in September
Petersburg, AK

Average rainfall in September - Petersburg, AK
  • Average rainfall in September: 5.12"

The wettest month (with the highest rainfall) is October (6.3").
The driest month (with the least rainfall) is May (2.01").

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Average rainfall days in September
Petersburg, AK

Average rainfall days in September - Petersburg, AK
  • Average rainfall days in September: 17.5 days

The month with the highest number of rainy days is October (20.1 days).
The month with the least rainy days is February (9.5 days).

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Average snowfall in September
Petersburg, AK

Average snowfall in September - Petersburg, AK
  • Average snowfall in September: 0"

The month with the highest snowfall is March (13.46").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Petersburg, AK

Average snowfall days in September - Petersburg, AK
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is March (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in September
Petersburg, AK

Average sea temperature in September - Petersburg, AK
  • Average sea temperature in September: 52°F

The best month for swimming (with the highest average sea temperature) is August (54.2°F).
The coldest month (with the lowest average sea temperature) is March (41°F).

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Average daylight in September /
Average sunshine in September
Petersburg, AK

Average daylight in September / Average sunshine in September - Petersburg, AK
  • Average daylight in September: 12h and 4min

The month with the longest days is June (Average daylight: 17h and 42min).
The month with the shortest days is December (Average daylight: 6h and 54min).

  • Average sunshine in September: 6h and 4min

The month with the most sunshine is May (Average sunshine: 7h and 24min).
The months with the least sunshine are January and November (Average sunshine: 3h and 24min).

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Average sunshine days in September
Petersburg, AK

Average sunshine days in September - Petersburg, AK
  • Average sunshine days in September: 11.5 days

The month with the most sunshine days is December (12.5 days).
The month with the least sunshine days is November (8 days).

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Average UV index in September
Petersburg, AK

Average UV index in September - Petersburg, AK
  • Average UV index in September: 2

The months with the highest UV index are July and August (UV index 4).
The months with the lowest UV index are November and December (UV index 1).

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Average cloud cover in September
Petersburg, AK

Average cloud cover in September - Petersburg, AK
  • Average cloud cover in September: 55

The month with the most cloud cover is January (Cloud cover 66).
The months with the least cloud cover are February and May (Cloud cover 54).

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Average visibility in September
Petersburg, AK

Average visibility in September - Petersburg, AK
  • Average visibility in September: 6mi

The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).

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Petersburg, Alaska, USA

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