September weather forecast
Ketchikan, AK

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Beautiful and colorful houses along the waterfront boardwalk on Creek Street in Ketchikan, Alaska
Beautiful and colorful houses along the waterfront boardwalk on Creek Street in Ketchikan, Alaska

Weather in September

The weather in Ketchikan, during September, undergoes a slow transition towards fall. Average temperatures take a slight dip compared to August, ranging from 48.7°F (9.3°C) to 56.3°F (13.5°C). With the rainfall clocking 6.85" (174mm), the city starts to experience frequent showers. As daylight shortens to 12.7 hours, the tones of autumn begin to color the city's landscapes. Ketchikan in September bears witness to changing seasons, as the brisk summer winds transition into a crisper fall.

Temperature

In September, Ketchikan notes an average high-temperature of a still refreshing 56.3°F (13.5°C), hardly different from the preceding month. In Ketchikan, the nightly September temperatures experience a slight descent from daily highs to an average low of 48.7°F (9.3°C).

Humidity

In September, the average relative humidity is 86%.

Rainfall

In Ketchikan, in September, during 19.3 rainfall days, 6.85" (174mm) of precipitation is typically accumulated. Throughout the year, in Ketchikan, Alaska, there are 221.8 rainfall days, and 80" (2032mm) of precipitation is accumulated.

Snowfall

June through October are months without snowfall.

Ocean temperature

In Ketchikan, the average seawater temperature in September is 53.2°F (11.8°C).
Note: In 53.2°F (11.8°C), even brief exposure to 55.4°F (13°C) feels biting, and anything less than 50°F (10°C) risks cold shock and impaired breathing, considering one's health.

Daylight

In September, the average length of the day in Ketchikan is 12h and 42min.
On the first day of September, sunrise is at 5:54 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 6:49 am and sunset at 6:23 pm AKDT.

Sunshine

In Ketchikan, the average sunshine in September is 6.3h.

UV index

In Ketchikan, the average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for average individuals.
Note: In September, the UV index of 3 transforms into the following advice:
Ensure safety - Sun damage prevention is strongly urged. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
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Frequently asked questions

What are the temperatures in Ketchikan in September?

The high-temperature, in September, in Ketchikan, is 56.3°F (13.5°C), while the low-temperature averages to 48.7°F (9.3°C).

What is the average humidity in September in Ketchikan?

In September, the average relative humidity in Ketchikan, Alaska, is 86%.

How many days does it rain in September in Ketchikan?

In September, in Ketchikan, Alaska, the rain falls for 19.3 days. Throughout September, 6.85" (174mm) of precipitation is accumulated.

When it does not snow in Ketchikan?

June through October are months without snowfall in Ketchikan, Alaska.

What is the water temperature in September in Ketchikan?

In Ketchikan, in September, the average water temperature is 53.2°F (11.8°C). Swimming in 53.2°F (11.8°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

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

In September, the average day length in Ketchikan, Alaska, is 12h and 42min.

When is the sunrise / sunset in September in Ketchikan?

In September, on the first day of the month, sunrise is at 5:54 am and sunset at 7:38 pm. On the last day of the month, in Ketchikan, Alaska, sunrise is at 6:49 am and sunset at 6:23 pm AKDT.

How many hours of sunshine does Ketchikan have in September?

The average sunshine duration in September in Ketchikan is 6.3h.

What is the UV index reading in September in Ketchikan?

In September, the average daily maximum UV index in Ketchikan is 3. A UV Index estimate of 3 to 5 represents a medium 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
Ketchikan, AK

Average temperature in September - Ketchikan, AK
  • Average high temperature in September: 56.3°F

The warmest months (with the highest average high temperature) are July and August (60.8°F).
The month with the lowest average high temperature is December (35.8°F).

  • Average low temperature in September: 48.7°F

The month with the highest average low temperature is August (52°F).
The coldest month (with the lowest average low temperature) is February (30.6°F).

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Average pressure in September
Ketchikan, AK

Average pressure in September - Ketchikan, AK
  • Average pressure in September: 29.93"Hg

The month with the highest atmospheric pressure is July (30.06"Hg).
The month with the lowest atmospheric pressure is November (29.8"Hg).

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Average wind speed in September
Ketchikan, AK

Average wind speed in September - Ketchikan, AK
  • Average wind speed in September: 6.2mph

The windiest month (with the highest average wind speed) is January (8.7mph).
The calmest months (with the lowest average wind speed) are July and August (5.3mph).

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Average humidity in September
Ketchikan, AK

Average humidity in September - Ketchikan, AK
  • Average humidity in September: 86%

The month with the highest relative humidity is January (88%).
The month with the lowest relative humidity is May (82%).

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Average rainfall in September
Ketchikan, AK

Average rainfall in September - Ketchikan, AK
  • Average rainfall in September: 6.85"

The wettest month (with the highest rainfall) is January (9.69").
The driest month (with the least rainfall) is May (3.46").

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Average rainfall days in September
Ketchikan, AK

Average rainfall days in September - Ketchikan, AK
  • Average rainfall days in September: 19.3 days

The month with the highest number of rainy days is November (21.4 days).
The month with the least rainy days is February (14.2 days).

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Average snowfall in September
Ketchikan, AK

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

The month with the highest snowfall is February (13.11").
The months with the least snowfall are June, July, August, September and October (0").

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Average snowfall days in September
Ketchikan, AK

Average snowfall days in September - Ketchikan, 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 sea temperature in September
Ketchikan, AK

Average sea temperature in September - Ketchikan, AK
  • Average sea temperature in September: 53.3°F

The best month for swimming (with the highest average sea temperature) is August (55.9°F).
The coldest month (with the lowest average sea temperature) is March (42.5°F).

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Average daylight in September /
Average sunshine in September
Ketchikan, AK

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

The month with the longest days is June (Average daylight: 17h and 24min).
The month with the shortest days is December (Average daylight: 7h and 12min).

  • Average sunshine in September: 6h and 2min

The month with the most sunshine is May (Average sunshine: 7h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).

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Average sunshine days in September
Ketchikan, AK

Average sunshine days in September - Ketchikan, AK
  • Average sunshine days in September: 9.9 days

The month with the most sunshine days is July (11.9 days).
The month with the least sunshine days is November (5.6 days).

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Average UV index in September
Ketchikan, AK

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

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

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Average cloud cover in September
Ketchikan, AK

Average cloud cover in September - Ketchikan, AK
  • Average cloud cover in September: 56

The month with the most cloud cover is January (Cloud cover 71).
The month with the least cloud cover is May (Cloud cover 55).

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Average visibility in September
Ketchikan, AK

Average visibility in September - Ketchikan, 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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Ketchikan, Alaska, USA

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