Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average sea temperature in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The start of September in Unalaska sees the average high-temperature at a still fresh 50°F (10°C), showing little difference from August's 53.2°F (11.8°C). Unalaska's September nights observe a minor shift from the daytime temperatures, resulting in an average dip to a chilly 47.1°F (8.4°C).Humidity
In September, the average relative humidity is 87%.Rainfall
In Unalaska, in September, during 19.8 rainfall days, 2.72" (69mm) of precipitation is typically accumulated. Throughout the year, there are 198.8 rainfall days, and 33.78" (858mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall in Unalaska.Ocean temperature
In September, the average ocean temperature in Unalaska is 48.6°F (9.2°C).Note: Caution: 48.6°F (9.2°C) temperatures below 50°F (10°C) during swimming can result in intense cold shock and quickened breathing.
Daylight
In September, the average length of the day is 12h and 40min.On the first day of the month, sunrise is at 8:16 am and sunset at 9:55 pm. On the last day of September, in Unalaska, sunrise is at 9:08 am and sunset at 8:43 pm AKDT.
Sunshine
In Unalaska, Alaska, the average sunshine in September is 4.7h.UV index
The average daily maximum UV index in September is 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: In September, a daily maximum UV index of 2 leads to the following instructions:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.
Frequently asked questions
What are the temperatures in Unalaska in September?
What is the average humidity in September in Unalaska?
How many days does it rain in September in Unalaska?
When it does not snow in Unalaska?
Does it snow in Unalaska in September?
How cold is the water in September in Unalaska?
How many hours of daylight does Unalaska have in September?
When are sunrise and sunset in September in Unalaska?
How long on average sun shines in September in Unalaska?
How high is the UV index in September in Unalaska?
Average temperature in September
Unalaska, AK
- Average high temperature in September: 50°F
The warmest month (with the highest average high temperature) is August (53.2°F).
The month with the lowest average high temperature is March (34.7°F).
- Average low temperature in September: 47.1°F
The month with the highest average low temperature is August (49.6°F).
The coldest month (with the lowest average low temperature) is March (30.7°F).
Average pressure in September
Unalaska, AK
- Average pressure in September: 29.79"Hg
The month with the highest atmospheric pressure is July (29.98"Hg).
The month with the lowest atmospheric pressure is January (29.5"Hg).
Average wind speed in September
Unalaska, AK
- Average wind speed in September: 12.9mph
The windiest months (with the highest average wind speed) are November and December (16.5mph).
The calmest month (with the lowest average wind speed) is July (9.1mph).
Average humidity in September
Unalaska, AK
- Average humidity in September: 87%
The month with the highest relative humidity is July (91%).
The months with the lowest relative humidity are November and December (80%).
Average rainfall in September
Unalaska, AK
- Average rainfall in September: 2.72"
The wettest month (with the highest rainfall) is December (4.21").
The driest month (with the least rainfall) is July (1.85").
Average rainfall days in September
Unalaska, AK
- Average rainfall days in September: 19.8 days
The month with the highest number of rainy days is October (21.8 days).
The month with the least rainy days is February (11.1 days).
Average snowfall in September
Unalaska, AK
- Average snowfall in September: 0"
The month with the highest snowfall is January (6.97").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Unalaska, AK
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (14.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
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: 12h and 4min
The month with the longest days is June (Average daylight: 17h and 0min).
The month with the shortest days is December (Average daylight: 7h and 30min).
- Average sunshine in September: 4h and 4min
The month with the most sunshine is June (Average sunshine: 5h and 48min).
The month with the least sunshine is December (Average sunshine: 2h and 0min).
Average sunshine days in September
Unalaska, AK
- Average sunshine days in September: 6.9 days
The month with the most sunshine days is August (9.7 days).
The month with the least sunshine days is April (3.8 days).
Average UV index in September
Unalaska, AK
- Average UV index in September: 2
The months with the highest UV index are July and August (UV index 3).
The months with the lowest UV index are February, March, April and November (UV index 1).
Average cloud cover in September
Unalaska, AK
- Average cloud cover in September: 66
The month with the most cloud cover is July (Cloud cover 74).
The months with the least cloud cover are September and October (Cloud cover 66).
Average visibility in September
Unalaska, AK
- Average visibility in September: 6mi
The months with the highest visibility are May, June, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March, April, July and December (5mi).
Unalaska, Alaska, USA
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