September weather forecastSandown, NH
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Sandown, New Hampshire, with an average temperature fluctuating between 71.2°F (21.8°C) and 54.1°F (12.3°C).Temperature
The transition into September is accompanied by a slight temperature decrease, with the average high-temperature shifting from a warm 79°F (26.1°C) in August to a pleasant 71.2°F (21.8°C). Nighttime temperatures hover around an average low of 54.1°F (12.3°C) in September.Humidity
In Sandown, the average relative humidity in September is 78%.Rainfall
The month with the least rainfall in Sandown, New Hampshire, is September, when the rain falls for 11.3 days and typically collects 1.5" (38mm) of precipitation.Snowfall
June through September are months without snowfall in Sandown.Daylight
In September, the average length of the day in Sandown is 12h and 29min.On the first day of September in Sandown, New Hampshire, sunrise is at 6:10 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:27 pm EDT.
Sunshine
In September, the average sunshine is 8.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.Note: In September, a daily maximum UV index of 4 leads to the following instructions:
Undertake precautions - Obligation exists to protect against skin and eye damage. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Sandown, NH
- Average high temperature in September: 71.2°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (31.3°F).
- Average low temperature in September: 54.1°F
The month with the highest average low temperature is July (61.3°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in September
Sandown, 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 (29.92"Hg).
Average wind speed in September
Sandown, NH
- Average wind speed in September: 6mph
The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).
Average humidity in September
Sandown, NH
- Average humidity in September: 78%
The month with the highest relative humidity is February (81%).
The month with the lowest relative humidity is April (73%).
Average rainfall in September
Sandown, NH
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is December (2.99").
The driest month (with the least rainfall) is September (1.5").
Average rainfall days in September
Sandown, NH
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is January (6.4 days).
Average snowfall in September
Sandown, NH
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.98").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Sandown, NH
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Sandown, NH
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 18min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in September
Sandown, NH
- Average sunshine days in September: 17.1 days
The month with the most sunshine days is November (17.3 days).
The month with the least sunshine days is April (13.6 days).
Average UV index in September
Sandown, NH
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Sandown, NH
- Average cloud cover in September: 37
The month with the most cloud cover is March (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 33).
Average visibility in September
Sandown, NH
- Average visibility in September: 5mi
The months with the highest visibility are January, March, April, June, October, November and December (6mi).
The months with the lowest visibility are February, May, July, August and September (5mi).





