September weather forecast and climate
Petersburg, AK

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

September, the first month of the autumn, in Petersburg, is still a cool month, with average temperature fluctuating between 54.3°F (12.4°C) and 46.4°F (8°C).

Temperature

In September, the average high-temperature is essentially the same as in August - a cool 54.3°F (12.4°C). In September, the average low-temperature is 46.4°F (8°C).

Humidity

In September, the average relative humidity is 84%.

Rainfall

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

Snowfall

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

Ocean temperature

In Petersburg, the average seawater temperature is 52°F (11.1°C).
Note: At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

Daylight

In September, the average length of the day in Petersburg is 12.7h.

Sunshine

In Petersburg, the average sunshine is 6.7h.

UV index

In September, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a minimal health hazard from the exposure to the Sun's UV rays for ordinary individuals.
Note: The daily maximum UV index of 2 interpret into the following advice:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the average humidity in September in Petersburg?

In September, the average relative humidity in Petersburg, Alaska, is 84%.

How much does it rain in Petersburg in September?

In September, in Petersburg, the rain falls for 17.5 days. Throughout September, 5.12" (130mm) of precipitation is accumulated.

When it does not snow in Petersburg?

June through September are months without snowfall in Petersburg.

Does it snow in Petersburg in September?

In Petersburg, Alaska, 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?

In September, the average length of the day is 12.7h.

How many hours of sunshine does Petersburg have in September?

In Petersburg, the average sunshine in September is 6.7h.

How high is the UV index in September in Petersburg?

The average daily maximum UV index in September in Petersburg is 2. A UV Index reading of 2, and below, represents a low health risk from the exposure to the Sun's UV rays.

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"

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

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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%

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").
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).
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: 12.7h

The month with the longest days is June (Average daylight: 17.7h).
The month with the shortest days is December (Average daylight: 6.9h).

  • Average sunshine in September: 6.7h

The month with the most sunshine is May (Average sunshine: 7.4h).
Months with the least sunshine are January and November (Average sunshine: 3.4).

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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

Months with the highest UV index are July and August (UV index 4).
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).
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

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

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