September weather forecastAlton Bay, NH
September
Weather in September
September, the first month of the autumn in Alton Bay, is still a pleasant month, with an average temperature ranging between max 69.6°F (20.9°C) and min 49.6°F (9.8°C).Temperature
The transition to September results in a modest reduction in average high-temperature, moving from a moderately hot 77.2°F (25.1°C) in August to a pleasant 69.6°F (20.9°C). The nighttime temperature, during September, averages of 49.6°F (9.8°C).Humidity
In Alton Bay, the average relative humidity in September is 80%.Rainfall
The month with the least rainfall in Alton Bay is September, when the rain falls for 10.8 days and typically collects 1.61" (41mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In Alton Bay, the average length of the day in September is 12h and 29min.On the first day of September in Alton Bay, sunrise is at 6:09 am and sunset at 7:19 pm. On the last day of the month, sunrise is at 6:42 am and sunset at 6:27 pm EDT.
Sunshine
In September, the average sunshine is 8.2h.UV index
In Alton Bay, the average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: In September, the maximum UV index of 3 suggests this advice:
Guard yourself - Precautionary measures against sun damage are advocated. When the Sun is at its strongest around midday, find shade and limit exposure. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Alton Bay, NH
- Average high temperature in September: 69.6°F
The warmest month (with the highest average high temperature) is July (78.3°F).
The month with the lowest average high temperature is January (26.1°F).
- Average low temperature in September: 49.6°F
The month with the highest average low temperature is July (57.6°F).
The coldest month (with the lowest average low temperature) is January (12.9°F).
Average pressure in September
Alton Bay, NH
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.06"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Alton Bay, NH
- Average wind speed in September: 4.8mph
The windiest months (with the highest average wind speed) are January and February (7.1mph).
The calmest months (with the lowest average wind speed) are July and August (4.7mph).
Average humidity in September
Alton Bay, NH
- Average humidity in September: 80%
The months with the highest relative humidity are January and February (86%).
The month with the lowest relative humidity is April (76%).
Average rainfall in September
Alton Bay, NH
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is October (3.19").
The driest month (with the least rainfall) is September (1.61").
Average rainfall days in September
Alton Bay, NH
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is April (15.8 days).
The month with the least rainy days is February (8.3 days).
Average snowfall in September
Alton Bay, NH
- Average snowfall in September: 0"
The month with the highest snowfall is February (9.84").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Alton Bay, NH
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (13.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Alton Bay, NH
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 8h and 12min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).
Average sunshine days in September
Alton Bay, NH
- Average sunshine days in September: 16.9 days
The month with the most sunshine days is September (16.9 days).
The month with the least sunshine days is April (11.4 days).
Average UV index in September
Alton Bay, NH
- Average UV index in September: 3
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Alton Bay, NH
- Average cloud cover in September: 39
The month with the most cloud cover is March (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 35).
Average visibility in September
Alton Bay, NH
- Average visibility in September: 4mi
The months with the highest visibility are January, March, April, May, June, July, August, October, November and December (5mi).
The months with the lowest visibility are February and September (4mi).
