September weather forecast
Anchorage, AK

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Wintertime in Anchorage, Alaska with mountains blanketed in snow
Wintertime in Anchorage, Alaska with mountains blanketed in snow

Weather in September

September marks the beginning of fall in Anchorage, as temperatures drop from August highs and daylight hours drastically shorten. Despite the melancholy of shrinking days, the city is ablaze with the vibrant colors of autumn foliage. Rainfall peaks at 1.93" (49mm) this month, the highest for the year, breathing a sprightly vigor into the natural surroundings. Wind strength remains steady, adding a crisp breeze to the somewhat cooler climate. With the capture of such an array of color and mood, Anchorage in September is a photographer's delight.

Temperature

Anchorage's September weather features a light decline in high-temperatures, reducing from a refreshing 59.5°F (15.3°C) in August to a cool 52.7°F (11.5°C). In Anchorage, the nighttime temperature shows a slight difference from the daytime high, averaging to a chilly 43.9°F (6.6°C) during September.

Humidity

The average relative humidity in September is 78%.

Rainfall

September is the month with the most rainfall in Anchorage. Rain falls for 16 days and accumulates 1.93" (49mm) of precipitation.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows in Anchorage. Throughout September, in the average 0.3 snowfall days, it receives 0.08" (2mm) of snow. In Anchorage, during the entire year, snow falls for 59.3 days and aggregates up to 23.5" (597mm) of snow.

Ocean temperature

In Anchorage, the average seawater temperature in September is 51.6°F (10.9°C).
Note: Swimming in 51.6°F (10.9°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

Daylight

The average length of the day in September in Anchorage is 12h and 52min.
On the first day of September, sunrise is at 6:53 am and sunset at 9:04 pm. On the last day of the month, sunrise is at 8:06 am and sunset at 7:32 pm AKDT.

Sunshine

In Anchorage, the average sunshine in September is 7.6h.

UV index

The average daily maximum UV index in September is 2. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for average individuals.
Note: In September, the maximum UV index of 2 suggests this advice:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Avoiding the Sun during its peak radiation time around midday is a healthy practice. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
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Frequently asked questions

What is the usual temperature for Anchorage in September?

During September, Anchorage experiences an average high-temperature of 52.7°F (11.5°C) and a low-temperature of 43.9°F (6.6°C).

What is the average humidity in September in Anchorage?

The average relative humidity in September is 78%.

What is the wettest month in Anchorage?

September is the month with the most rainfall in Anchorage, Alaska. Rain falls for 16 days and accumulates 1.93" (49mm) of precipitation.

How much does it rain in Anchorage in September?

In Anchorage, Alaska, during September, the rain falls for 16 days and regularly aggregates up to 1.93" (49mm) of precipitation.

When does it start snowing in Anchorage?

September is the first month it typically snows in Anchorage. Throughout September, in the average 0.3 snowfall days, it receives 0.08" (2mm) of snow.

What is the ocean temperature in September in Anchorage?

In Anchorage, Alaska, the average seawater temperature in September is 51.6°F (10.9°C). Swimming in 51.6°F (10.9°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.

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

In September, the average day length in Anchorage, Alaska, is 12h and 52min.

When is the sunrise / sunset in September in Anchorage?

On the first day of September in Anchorage, Alaska, sunrise is at 6:53 am and sunset at 9:04 pm. On the last day of the month, sunrise is at 8:06 am and sunset at 7:32 pm AKDT.

How long on average sun shines in September in Anchorage?

The average sunshine duration in September is 7.6h.

What is the UV index intensity in September in Anchorage?

In September, the average daily maximum UV index in Anchorage is 2. A UV Index estimate of 2, and below, represents a minimal hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Anchorage, AK

Average temperature in September - Anchorage, AK
  • Average high temperature in September: 52.7°F

The warmest month (with the highest average high temperature) is July (61.9°F).
The month with the lowest average high temperature is January (20.3°F).

  • Average low temperature in September: 43.9°F

The month with the highest average low temperature is July (51.3°F).
The coldest month (with the lowest average low temperature) is January (13.1°F).

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Average pressure in September
Anchorage, AK

Average pressure in September - Anchorage, AK
  • Average pressure in September: 29.74"Hg

The month with the highest atmospheric pressure is July (29.96"Hg).
The months with the lowest atmospheric pressure are November and December (29.67"Hg).

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Average wind speed in September
Anchorage, AK

Average wind speed in September - Anchorage, AK
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is November (6.3mph).
The calmest month (with the lowest average wind speed) is July (4.5mph).

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Average humidity in September
Anchorage, AK

Average humidity in September - Anchorage, AK
  • Average humidity in September: 78%

The months with the highest relative humidity are January, February and March (86%).
The month with the lowest relative humidity is May (68%).

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Average rainfall in September
Anchorage, AK

Average rainfall in September - Anchorage, AK
  • Average rainfall in September: 1.93"

The wettest month (with the highest rainfall) is September (1.93").
The driest month (with the least rainfall) is May (0.55").

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Average rainfall days in September
Anchorage, AK

Average rainfall days in September - Anchorage, AK
  • Average rainfall days in September: 16 days

The month with the highest number of rainy days is August (17.9 days).
The month with the least rainy days is February (7 days).

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Average snowfall in September
Anchorage, AK

Average snowfall in September - Anchorage, AK
  • Average snowfall in September: 0.08"

The month with the highest snowfall is December (5.51").
The months with the least snowfall are June, July and August (0").

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Average snowfall days in September
Anchorage, AK

Average snowfall days in September - Anchorage, AK
  • Average snowfall days in September: 0.3 days

The month with the highest number of snowfall days is December (11.6 days).
The months with the least snowfall days are June, July and August (0 days).

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Average sea temperature in September
Anchorage, AK

Average sea temperature in September - Anchorage, AK
  • Average sea temperature in September: 51.6°F

The best month for swimming (with the highest average sea temperature) is August (53.1°F).
The coldest month (with the lowest average sea temperature) is February (35.8°F).

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

Average daylight in September / Average sunshine in September - Anchorage, AK
  • Average daylight in September: 12h and 5min

The month with the longest days is June (Average daylight: 19h and 12min).
The month with the shortest days is December (Average daylight: 5h and 36min).

  • Average sunshine in September: 7h and 4min

The months with the most sunshine are May and June (Average sunshine: 11h and 42min).
The month with the least sunshine is December (Average sunshine: 3h and 48min).

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Average sunshine days in September
Anchorage, AK

Average sunshine days in September - Anchorage, AK
  • Average sunshine days in September: 11.1 days

The month with the most sunshine days is January (16.9 days).
The month with the least sunshine days is September (11.1 days).

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Average UV index in September
Anchorage, AK

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

The months with the highest UV index are June and July (UV index 4).
The month with the lowest UV index is February (UV index 1).

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Average cloud cover in September
Anchorage, AK

Average cloud cover in September - Anchorage, AK
  • Average cloud cover in September: 44

The month with the most cloud cover is December (Cloud cover 47).
The month with the least cloud cover is May (Cloud cover 38).

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Average visibility in September
Anchorage, AK

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

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

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Anchorage, Alaska, USA

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