September weather forecastPetersburg, AK
September
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
With the start of September, Petersburg measures an average high-temperature of a fresh 54.3°F (12.4°C), not significantly differing from August's 59°F (15°C). In September, a low-temperature average of 46.4°F (8°C) is characteristic of Petersburg, marking a minor shift from daytime temperatures.Humidity
In Petersburg, the average relative humidity in September is 84%.Rainfall
In Petersburg, in September, during 17.5 rainfall days, 5.12" (130mm) of precipitation is typically accumulated. Throughout the year, there are 197.9 rainfall days, and 53.03" (1347mm) of precipitation is accumulated.Snowfall
In Petersburg, snow does not fall in June through September.Ocean temperature
In September, the average ocean temperature is 52°F (11.1°C).Note: Swimming in 52°F (11.1°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.
Daylight
In Petersburg, the average length of the day in September 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, sunrise is at 6:55 am and sunset at 6:27 pm AKDT.
Sunshine
The average sunshine in September is 6.7h.UV index
In Petersburg, Alaska, 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 Sun's UV rays for ordinary individuals.Note: A daily maximum UV index of 2 in September translates into the following instructions:
Despite the majority tolerating prolonged sun exposure, those with sensitive skin, infants, and children demand continual protection. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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").
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).
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).
Average daylight in September /
Average sunshine in September
Petersburg, AK
- Average daylight in September: 12h and 42min
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 42min
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).
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).
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).
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).
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).
