September weather forecast
Saint John Harbor, AK

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Weather in September

The first month of the autumn, September, is also a fresh month in Saint John Harbor, Alaska, with an average temperature fluctuating between 46.4°F (8°C) and 54.3°F (12.4°C).

Temperature

As August turns into September, the average high-temperatures rest at a cool 54.3°F (12.4°C), showing a minor variation from the prior month. Saint John Harbor notes a steady average temperature of 46.4°F (8°C) during the nights of September.

Humidity

The average relative humidity in September in Saint John Harbor is 84%.

Rainfall

In Saint John Harbor, in September, during 17.5 rainfall days, 5.12" (130mm) of precipitation is typically accumulated. In Saint John Harbor, during the entire year, the rain falls for 197.9 days and collects up to 53.03" (1347mm) of precipitation.

Snowfall

In Saint John Harbor, snow does not fall in June through September.

Daylight

In September, the average length of the day in Saint John Harbor is 12h and 43min.
On the first day of September, sunrise is at 5:57 am and sunset at 7:45 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:27 pm AKDT.

Sunshine

In September, the average sunshine in Saint John Harbor is 6.7h.

UV index

In Saint John Harbor, the average daily maximum UV index in September is 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A daily maximum UV index of 2 in September translates into the following instructions:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Stay sun-safe with clothing that is both closely woven and worn loosely.
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Frequently asked questions

What is the temperature in September in Saint John Harbor?

During September, Saint John Harbor experiences an average high-temperature of 54.3°F (12.4°C) and a low-temperature of 46.4°F (8°C).

What is the average humidity in September in Saint John Harbor?

In Saint John Harbor, the average relative humidity in September is 84%.

How many days does it rain in September in Saint John Harbor?

In September, the rain falls for 17.5 days. Throughout September, 5.12" (130mm) of precipitation is accumulated.

When it does not snow in Saint John Harbor?

June through September are months without snowfall in Saint John Harbor.

Does it snow in Saint John Harbor in September?

In Saint John Harbor, Alaska, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September in Saint John Harbor?

In Saint John Harbor, the average day length in September is 12h and 43min.

What time are sunrise and sunset in September in Saint John Harbor?

On the first day of September in Saint John Harbor, Alaska, sunrise is at 5:57 am and sunset at 7:45 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:27 pm AKDT.

How many hours of sunshine does Saint John Harbor have in September?

The average sunshine duration in September is 6.7h.

What is the UV index reading in September in Saint John Harbor?

The average daily maximum UV index in September is 2. A UV Index estimate of 2, and below, represents a low health risk from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Saint John Harbor, AK

Average temperature in September - Saint John Harbor, AK
  • Average high temperature in September: 54.3°F

The warmest month (with the highest average high temperature) is July (59.7°F).
The month with the lowest average high temperature is December (32.4°F).

  • Average low temperature in September: 46.4°F

The month with the highest average low temperature is July (50.2°F).
The coldest month (with the lowest average low temperature) is February (25.9°F).

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Average pressure in September
Saint John Harbor, AK

Average pressure in September - Saint John Harbor, AK
  • Average pressure in September: 29.91"Hg

The month with the highest atmospheric pressure is July (30.05"Hg).
The month with the lowest atmospheric pressure is November (29.8"Hg).

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Average wind speed in September
Saint John Harbor, AK

Average wind speed in September - Saint John Harbor, AK
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is January (8.2mph).
The calmest month (with the lowest average wind speed) is July (3.9mph).

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Average humidity in September
Saint John Harbor, AK

Average humidity in September - Saint John Harbor, AK
  • Average humidity in September: 84%

The months with the highest relative humidity are January and August (86%).
The month with the lowest relative humidity is May (81%).

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Average rainfall in September
Saint John Harbor, AK

Average rainfall in September - Saint John Harbor, AK
  • Average rainfall in September: 5.12"

The wettest month (with the highest rainfall) is October (6.3").
The driest month (with the least rainfall) is May (2.01").

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Average rainfall days in September
Saint John Harbor, AK

Average rainfall days in September - Saint John Harbor, AK
  • Average rainfall days in September: 17.5 days

The month with the highest number of rainy days is October (20.1 days).
The month with the least rainy days is February (9.5 days).

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Average snowfall in September
Saint John Harbor, AK

Average snowfall in September - Saint John Harbor, AK
  • Average snowfall in September: 0"

The month with the highest snowfall is March (13.46").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Saint John Harbor, AK

Average snowfall days in September - Saint John Harbor, AK
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is March (10.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in September /
Average sunshine in September
Saint John Harbor, AK

Average daylight in September / Average sunshine in September - Saint John Harbor, AK
  • Average daylight in September: 12h and 4min

The month with the longest days is June (Average daylight: 17h and 36min).
The month with the shortest days is December (Average daylight: 7h and 0min).

  • Average sunshine in September: 6h and 4min

The month with the most sunshine is May (Average sunshine: 7h and 24min).
The months with the least sunshine are January and November (Average sunshine: 3h and 24min).

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Average sunshine days in September
Saint John Harbor, AK

Average sunshine days in September - Saint John Harbor, AK
  • Average sunshine days in September: 11.5 days

The month with the most sunshine days is December (12.5 days).
The month with the least sunshine days is November (8 days).

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Average UV index in September
Saint John Harbor, AK

Average UV index in September - Saint John Harbor, AK
  • Average UV index in September: 2

The months with the highest UV index are July and August (UV index 4).
The months with the lowest UV index are November and December (UV index 1).

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Average cloud cover in September
Saint John Harbor, AK

Average cloud cover in September - Saint John Harbor, AK
  • Average cloud cover in September: 55

The month with the most cloud cover is January (Cloud cover 66).
The months with the least cloud cover are February and May (Cloud cover 54).

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Average visibility in September
Saint John Harbor, AK

Average visibility in September - Saint John Harbor, AK
  • Average visibility in September: 6mi

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

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Saint John Harbor, Alaska, USA

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