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

September weather forecast and climate
Unalaska, AK

September, the first month of the autumn, in Unalaska, is also a fresh month, with average temperature fluctuating between 43.5°F (6.4°C) and 54°F (12.2°C).

Temperature

In September, the average high-temperature is essentially the same as in August - a fresh 54°F (12.2°C). The average low-temperature, in Unalaska, is 43.5°F (6.4°C).

Rainfall

In September, the rain falls for 18 days. Throughout September, 5.2" (132.3mm) of precipitation is accumulated. In Unalaska, during the entire year, the rain falls for 223 days and collects up to 60.9" (1545.8mm) of precipitation.

Snowfall

June through September are months without snowfall.

Ocean temperature

In Unalaska, in September, the average water temperature is 48.6°F (9.2°C).
Note: Swimming in 48.6°F (9.2°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.

Daylight

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

Sunshine

In September, the average sunshine is 6h.

UV index

In September, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from the exposure to the Sun's UV radiation for the average person.
Note: The daily maximum UV index of 3 in September interpret into the following advice:
Take precautions. Light skin individuals may get burned in less than 30 minutes. 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.

What is the temperature in September in Unalaska?

In September, the average high-temperature is 54°F (12.2°C), and the average low-temperature is 43.5°F (6.4°C).

How much does it rain in Unalaska in September?

In Unalaska, in September, during 18 rainfall days, 5.2" (132.3mm) of precipitation is typically accumulated.

Does it snow in Unalaska in September?

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

When it does not snow in Unalaska?

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

What is the water temperature in September in Unalaska?

In Unalaska, in September, the average water temperature is 48.6°F (9.2°C). Swimming in 48.6°F (9.2°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

How many hours of daylight does Unalaska have in September?

The average length of the day in September in Unalaska is 12.7h.

How many hours of sunshine does Unalaska have in September?

The average sunshine in September in Unalaska is 6h.

How high is the UV index in September in Unalaska?

In Unalaska, Alaska, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a medium hazard to health from unsafe exposure to the Sun's UV rays.
Average temperature in September - Unalaska, AK
  • Average high temperature in September: 54°F

The warmest month (with the highest average high temperature) is August (58.9°F).
The month with the lowest average high temperature is January (36.8°F).

  • Average low temperature in September: 43.5°F

The month with the highest average low temperature is August (47.7°F).
The coldest month (with the lowest average low temperature) is February (27.6°F).

Average rainfall in September - Unalaska, AK
  • Average rainfall in September: 5.2"

The wettest month (with the highest rainfall) is December (7.9").
The driest month (with the lowest rainfall) is July (2.2").

Average rainfall days in September - Unalaska, AK
  • Average rainfall days in September: 18 days

Months with the highest number of rainy days are October, November and December (23 days).
The month with the lowest number of rainy days is July (13 days).

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

The month with the highest snowfall is January (23.8").
Months with the lowest snowfall are June, July, August and September (0").

Average sea temperature in September - Unalaska, AK
  • Average sea temperature in September: 48.5°F

The best month for swimming (with the highest average sea temperature) is August (50.1°F).
The coldest month (with the lowest average sea temperature) is February (38.8°F).

Average daylight in September / Average sunshine in September - Unalaska, AK
  • Average daylight in September: 12.7h

The month with the longest days is June (Average daylight: 17h).
The month with shortest days is December (Average daylight: 7.5h).

  • Average sunshine in September: 6h

Months with most sunshine are May and June (Average sunshine: 8h).
Months with least sunshine are November and December (Average sunshine: 5).

Average UV index in September - Unalaska, AK
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 6).
Months with the lowest UV index are January and December (UV index 0).