September weather forecastKetchikan, AK
September
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
September begins with an average high-temperature of a mild 56.3°F (13.5°C), reflecting close similarity to the preceding month. Ketchikan observes a consistent average low-temperature of 48.7°F (9.3°C) throughout September nights.Humidity
In September, the average relative humidity in Ketchikan is 86%.Rainfall
In Ketchikan, in September, during 19.3 rainfall days, 6.85" (174mm) of precipitation is typically accumulated. In Ketchikan, during the entire year, the rain falls for 221.8 days and collects up to 80" (2032mm) of precipitation.Snowfall
June through October are months without snowfall in Ketchikan.Ocean temperature
In Ketchikan, the average seawater temperature in September is 53.2°F (11.8°C).Note: It is advised against swimming in 53.2°F (11.8°C) when it drops below 50°F (10°C). Such temperatures can cause extreme cold shock, leading to hyperventilation.
Daylight
The average length of the day in September is 12h and 42min.On the first day of the month, sunrise is at 5:54 am and sunset at 7:38 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:23 pm AKDT.
Sunshine
In September, the average sunshine is 6.3h.UV index
In September, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the maximum UV index of 3 suggests these recommendations:
Ensure safety - Sun damage prevention is strongly urged. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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").
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).
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).
Average daylight in September /
Average sunshine in September
Ketchikan, AK
- Average daylight in September: 12h and 42min
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 18min
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).
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).
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).
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).
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).
