Anchorage
Alaska, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Anchorage, AK

Wintertime in Anchorage, Alaska, with mountains blanketed in snow
Wintertime in Anchorage, Alaska, with mountains blanketed in snow
September, the first month of the autumn, in Anchorage, is still a mild month, with average temperature fluctuating between 41.2°F (5.1°C) and 55.6°F (13.1°C).

Temperature

In September, the average high-temperature marginally drops, from an enjoyable 63.5°F (17.5°C) in August, to a moderate 55.6°F (13.1°C). In September, in Anchorage, the average low-temperature is 41.2°F (5.1°C).

Humidity

The average relative humidity in September is 75.9%.

Rainfall

In Anchorage, Alaska, during September, the rain falls for 14.5 days and regularly aggregates up to 3" (75.7mm) of precipitation. Throughout the year, there are 115.1 rainfall days, and 16.7" (423.4mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall in Anchorage, Alaska.

Ocean temperature

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

In September, the average length of the day in Anchorage is 12.8h.

Sunshine

The average sunshine in September is 5.3h.

UV index

The average daily maximum UV index in Anchorage, Alaska, is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from the exposure to the Sun's UV radiation for average individuals.
In September, the average maximum UV index of 2 translate into the following recommendations:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.

What is the temperature in September in Anchorage?

In September, in Anchorage, the average high-temperature is 55.6°F (13.1°C), and the average low-temperature is 41.2°F (5.1°C).

What is the average humidity in September in Anchorage?

In September, the average relative humidity is 75.9%.

How many days does it rain in September in Anchorage?

In Anchorage, in September, it is raining for 14.5 days, with typically 3" (75.7mm) of accumulated precipitation.

When does it start snowing in Anchorage?

September is the first month it typically snows in Anchorage, Alaska. Throughout September, in the average 0.2 snowfall days, it receives 0.5" (12.7mm) of snow.

How cold is the water in September in Anchorage?

In September, the average ocean temperature is 51.6°F (10.9°C). 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.

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

The average length of the day in September is 12.8h.

How long on average sun shines in September in Anchorage?

In September, the average sunshine is 5.3h.

What is the UV index reading in September in Anchorage?

In September, the average daily maximum UV index in Anchorage is 2. A UV Index value of 2, and less, symbolizes a low health threat from the exposure to the Sun's UV radiation.
Average temperature in September - Anchorage, AK
  • Average high temperature in September: 55.6°F

The warmest month (with the highest average high temperature) is July (65.4°F).
The month with the lowest average high temperature is January (22.7°F).

  • Average low temperature in September: 41.1°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 (11.4°F).

Average humidity in September - Anchorage, AK
  • Average humidity in September: 75.9%

Months with the highest relative humidity are November and December (77.1%).
The month with the lowest relative humidity is May (61.6%).

Average rainfall in September - Anchorage, AK
  • Average rainfall in September: 3"

The wettest month (with the highest rainfall) is August (3.3").
The driest month (with the lowest rainfall) is April (0.5").

Average rainfall days in September - Anchorage, AK
  • Average rainfall days in September: 14.5 days

The month with the highest number of rainy days is September (14.5 days).
The month with the lowest number of rainy days is April (5.5 days).

Average snowfall in September - Anchorage, AK
  • Average snowfall in September: 0.5"

The month with the highest snowfall is December (20.5").
Months with the lowest snowfall are June, July and August (0").

Average snowfall days in September - Anchorage, AK
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (10.5 days).
Months with the lowest number of snowfall days are June, July and August (0 days).

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).

Average daylight in September / Average sunshine in September - Anchorage, AK
  • Average daylight in September: 12.8h

The month with the longest days is June (Average daylight: 19.2h).
The month with shortest days is December (Average daylight: 5.6h).

  • Average sunshine in September: 5.3h

The month with most sunshine is May (Average sunshine: 9.3h).
The month with least sunshine is December (Average sunshine: 1.7h).

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

Months with the highest UV index are June and July (UV index 5).
Months with the lowest UV index are January, February, November and December (UV index 0).