September weather forecastNassau, DE
September
Weather in September
The first month of the autumn, September, is still a warm month in Nassau, Delaware, with an average temperature varying between 67.3°F (19.6°C) and 74.1°F (23.4°C).Temperature
A mild drop in Nassau's average high-temperature is observed in September, transitioning from a warm 79.5°F (26.4°C) in August to a still moderately hot 74.1°F (23.4°C). Nassau indicates a consistently low-temperature of 67.3°F (19.6°C) during the nights of September.Humidity
In September, the average relative humidity in Nassau is 78%.Rainfall
In Nassau, in September, during 14.8 rainfall days, 2.68" (68mm) of precipitation is typically accumulated. Throughout the year, there are 173.6 rainfall days, and 36.97" (939mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In Nassau, the average length of the day in September is 12h and 26min.On the first day of September in Nassau, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:44 pm EDT.
Sunshine
The average sunshine in September is 9.6h.UV index
In Nassau, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.Note: The maximum UV index of 5 during September leads to these instructions:
Exercise prevention - Protecting skin and eyes from harm is required. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. 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
Nassau, DE
- Average high temperature in September: 74.1°F
The warmest month (with the highest average high temperature) is July (80.6°F).
The month with the lowest average high temperature is January (41.2°F).
- Average low temperature in September: 67.3°F
The month with the highest average low temperature is July (73°F).
The coldest month (with the lowest average low temperature) is January (32°F).
Average pressure in September
Nassau, DE
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Nassau, DE
- Average wind speed in September: 9.9mph
The windiest month (with the highest average wind speed) is January (12.5mph).
The calmest month (with the lowest average wind speed) is August (8.3mph).
Average humidity in September
Nassau, DE
- Average humidity in September: 78%
The month with the highest relative humidity is May (81%).
The month with the lowest relative humidity is November (73%).
Average rainfall in September
Nassau, DE
- Average rainfall in September: 2.68"
The wettest month (with the highest rainfall) is August (4.13").
The driest month (with the least rainfall) is January (2.2").
Average rainfall days in September
Nassau, DE
- Average rainfall days in September: 14.8 days
The month with the highest number of rainy days is July (18.6 days).
The month with the least rainy days is January (9.6 days).
Average snowfall in September
Nassau, DE
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.98").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Nassau, DE
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (3.7 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Nassau, DE
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 36min
The month with the most sunshine is July (Average sunshine: 11h and 0min).
The month with the least sunshine is February (Average sunshine: 5h and 0min).
Average sunshine days in September
Nassau, DE
- Average sunshine days in September: 12.2 days
The month with the most sunshine days is November (17.6 days).
The month with the least sunshine days is May (9.8 days).
Average UV index in September
Nassau, DE
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in September
Nassau, DE
- Average cloud cover in September: 30
The months with the most cloud cover are February and March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 26).
Average visibility in September
Nassau, DE
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
