September weather forecastLewes, DE
September
Weather in September
Subtle shifts in the weather start to emerge in September, indicating the beginning of autumn. There’s a clear fall in temperature when compared to August, with morning lows recorded at 67.3°F (19.6°C) and highs around 74.1°F (23.4°C). As summer recedes, September continues to have no snowfall days, underlining the transition into fall. Along with decreasing temperatures, the weather also sees an increase in wind speeds compared to the summer months. The blend of cooling weather and lingering summer warmth creates an engaging seasonal fusion in the atmosphere of Lewes.Temperature
Lewes's transition into September involves a gentle shift in temperature, receding from 79.5°F (26.4°C) in August to a still moderately hot 74.1°F (23.4°C). In September, Lewes's nighttime temperatures demonstrate a slight decrease, stabilizing at an average of 67.3°F (19.6°C).Humidity
The average relative humidity in September is 78%.Rainfall
In Lewes, 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.Ocean temperature
In September, the average ocean temperature is 72.9°F (22.7°C).Note: Given an individual's cold sensitivity, considering factors like sunshine, wind, and air temperature, a brief swim in 72.9°F (22.7°C) water might be pleasurable. (FYI: The standard water temperature for Olympic swimming contests is 77°F (25°C) to 82.4°F (28°C).)
Daylight
In Lewes, the average length of the day in September is 12h and 26min.On the first day of September, 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
In September, the average sunshine is 9.6h.UV index
In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: The daily high UV index of 5 during September translates into the following recommendations:
Act with care - The suggestion to avoid sunburn is emphasized. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Alert! UV radiation becomes sharper due to reflections from sand and water.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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 sea temperature in September
Lewes, DE
- Average sea temperature in September: 72.8°F
The best month for swimming (with the highest average sea temperature) is August (76.9°F).
The coldest month (with the lowest average sea temperature) is February (40.7°F).
Average daylight in September /
Average sunshine in September
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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
Lewes, 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).
