September weather forecastDelaware City, DE
September
Weather in September
Delaware City, in September, witnesses the onset of autumn marked by milder temperatures and reduced daylight hours. The weather remains largely dry, combined with cooler evenings that signal the departure of summer. Despite this, September continues to embrace warmth with high temperatures averaging 77°F (25°C). The decrease in humidity and fewer rainfall days compared to August mark the shift towards autumn. September's comfortable conditions make it an ideal month for enjoying outdoor activities.Temperature
With September's onset, the weather in Delaware City reveals a slight temperature decrease, transitioning from a moderately hot 83.5°F (28.6°C) in August to a still warm 77°F (25°C). Delaware City's temperature drops to an average low of 60.8°F (16°C) during the nights of September.Humidity
The average relative humidity in September is 77%.Rainfall
In Delaware City, in September, it is raining for 12.5 days, with typically 1.65" (42mm) of accumulated precipitation. Throughout the year, there are 145.9 rainfall days, and 24.45" (621mm) of precipitation is accumulated.Snowfall
In Delaware City, snow does not fall in May through October.Ocean temperature
In Delaware City, in September, the average water temperature is 72.1°F (22.3°C).Note: Consideration of an individual's cold resistance, combined with conditions like sunshine, wind, and temperature, suggests that swimming in 72.1°F (22.3°C) water can be delightful. (Olympic swimming is usually in 77°F (25°C) to 82.4°F (28°C) water.)
Daylight
In Delaware City, Delaware, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:31 am and sunset at 7:32 pm. On the last day of September, sunrise is at 6:58 am and sunset at 6:45 pm EDT.
Sunshine
In September, the average sunshine is 9.2h.UV index
The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: A maximum high UV index of 5 in September translates into the following recommendations:
Be vigilant - Preventing sunburn is recommended. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Stay vigilant! UV rays get a boost in intensity due to sand and water reflections.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Delaware City, DE
- Average high temperature in September: 77°F
The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (38.3°F).
- Average low temperature in September: 60.8°F
The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (26.8°F).
Average pressure in September
Delaware City, DE
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in September
Delaware City, DE
- Average wind speed in September: 6.1mph
The windiest months (with the highest average wind speed) are February and March (8.9mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).
Average humidity in September
Delaware City, DE
- Average humidity in September: 77%
The month with the highest relative humidity is October (78%).
The month with the lowest relative humidity is April (72%).
Average rainfall in September
Delaware City, DE
- Average rainfall in September: 1.65"
The wettest month (with the highest rainfall) is August (3.11").
The driest month (with the least rainfall) is January (1.54").
Average rainfall days in September
Delaware City, DE
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (16.4 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in September
Delaware City, DE
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.65").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Delaware City, DE
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Delaware City, DE
- Average sea temperature in September: 72.1°F
The best month for swimming (with the highest average sea temperature) is August (76.3°F).
The coldest month (with the lowest average sea temperature) is February (40.9°F).
Average daylight in September /
Average sunshine in September
Delaware City, DE
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 9h and 12min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 54min).
Average sunshine days in September
Delaware City, DE
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
Delaware City, 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, February, November and December (UV index 2).
Average cloud cover in September
Delaware City, DE
- Average cloud cover in September: 36
The months with the most cloud cover are February and March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in September
Delaware City, 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).
