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
With September's arrival, Unalaska's weather records an average high-temperature of a still cool 50°F (10°C), marking little difference from August's 53.2°F (11.8°C). An average low-temperature of 47.1°F (8.4°C) is witnessed throughout the month of September, a mere drop from the daytime peak.Humidity
In Unalaska, the average relative humidity in September is 87%.Rainfall
In Unalaska, in September, during 19.8 rainfall days, 2.72" (69mm) of precipitation is typically accumulated. In Unalaska, during the entire year, the rain falls for 198.8 days and collects up to 33.78" (858mm) 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: Without suitable protection, venturing into 48.6°F (9.2°C) waters cooler than 50°F (10°C) can lead to pronounced cold shock and rapid breaths.
Daylight
In September, the average length of the day is 12h and 40min.On the first day of September, sunrise is at 8:16 am and sunset at 9:55 pm. On the last day of the month, sunrise is at 9:08 am and sunset at 8:43 pm AKDT.
Sunshine
The average sunshine in September is 4.7h.UV index
In Unalaska, 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 rays for ordinary individuals.Note: In September, the average maximum UV index of 2 translates into the following recommendations:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Unalaska in September?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
How cold is the water in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How long on average sun shines in September in Unalaska?
What is the UV index intensity in September?
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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