September weather forecastMendham, NJ
September
Weather in September
September, the first month of the autumn in Mendham, is also a moderately hot month, with an average temperature fluctuating between 56.8°F (13.8°C) and 74.5°F (23.6°C).Temperature
The arrival of September is marked by a minor reduction in average high-temperature, sliding from 81.3°F (27.4°C) in August to a still moderately hot 74.5°F (23.6°C). Mendham experiences an average nighttime temperature of 56.8°F (13.8°C) in the month of September.Humidity
In September, the average relative humidity in Mendham is 78%.Rainfall
The month with the least rainfall is September, when the rain falls for 12.9 days and typically collects 1.85" (47mm) of precipitation.Snowfall
In Mendham, snow does not fall in June through September.Daylight
In Mendham, New Jersey, the average length of the day in September is 12h and 27min.On the first day of the month, sunrise is at 6:25 am and sunset at 7:30 pm. On the last day of September, sunrise is at 6:54 am and sunset at 6:41 pm EDT.
Sunshine
In September, the average sunshine is 8.7h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum UV index, 4 during September, leads to the following recommendations:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Mendham, NJ
- Average high temperature in September: 74.5°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (35.1°F).
- Average low temperature in September: 56.8°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (22.3°F).
Average pressure in September
Mendham, NJ
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Mendham, NJ
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is March (8.3mph).
The calmest month (with the lowest average wind speed) is August (5.1mph).
Average humidity in September
Mendham, NJ
- Average humidity in September: 78%
The months with the highest relative humidity are February and October (80%).
The month with the lowest relative humidity is April (75%).
Average rainfall in September
Mendham, NJ
- Average rainfall in September: 1.85"
The wettest month (with the highest rainfall) is December (3.39").
The driest month (with the least rainfall) is September (1.85").
Average rainfall days in September
Mendham, NJ
- Average rainfall days in September: 12.9 days
The months with the highest number of rainy days are May and July (17.3 days).
The month with the least rainy days is January (8.9 days).
Average snowfall in September
Mendham, NJ
- Average snowfall in September: 0"
The month with the highest snowfall is March (4.49").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Mendham, NJ
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Mendham, NJ
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 8h and 42min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in September
Mendham, NJ
- Average sunshine days in September: 15 days
The month with the most sunshine days is November (17.6 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in September
Mendham, NJ
- Average UV index in September: 4
The months with the highest UV index are June and July (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
Mendham, NJ
- Average cloud cover in September: 40
The months with the most cloud cover are February and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 33).
Average visibility in September
Mendham, NJ
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, June, July, August, November and December (6mi).
The months with the lowest visibility are May, September and October (5mi).
