September weather forecastSaint John Harbor, AK
September
Weather in September
September, the first month of the autumn in Saint John Harbor, is also a fresh month, with an average temperature varying between 54.3°F (12.4°C) and 46.4°F (8°C).Temperature
Saint John Harbor experiences an average high-temperature of a cool 54.3°F (12.4°C) in September, marking an insignificant shift from 59°F (15°C) in August. Saint John Harbor maintains a minor drop in temperature during September nights, with averages of 46.4°F (8°C).Humidity
The average relative humidity in September in Saint John Harbor is 84%.Rainfall
In Saint John Harbor, in September, it is raining for 17.5 days, with typically 5.12" (130mm) of accumulated precipitation. Throughout the year, in Saint John Harbor, there are 197.9 rainfall days, and 53.03" (1347mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In Saint John Harbor, the average length of the day in September 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
The average sunshine in September is 6.7h.UV index
In Saint John Harbor, the average daily maximum UV index in September is 2. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for the average person.Note: In September, an average UV index of 2 transforms into the following instructions:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. During midday, the Sun's radiation is strongest, and it's advisable to reduce direct exposure. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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").
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).
Average daylight in September /
Average sunshine in September
Saint John Harbor, AK
- Average daylight in September: 12h and 42min
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 42min
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).
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).
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).
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).
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).
