Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The onset of September brings a small shift in high-temperatures, falling from a warm 80.4°F (26.9°C) in August to an agreeable 73.2°F (22.9°C). An average nighttime temperature of 62.1°F (16.7°C) is witnessed throughout September.Humidity
In Darien, Connecticut, the average relative humidity in September is 74%.Rainfall
In Darien, during September, the rain falls for 13.1 days and regularly aggregates up to 2.76" (70mm) of precipitation. In Darien, Connecticut, during the entire year, the rain falls for 166.4 days and collects up to 38.7" (983mm) of precipitation.Snowfall
In Darien, snow does not fall in May through October.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:21 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:50 am and sunset at 6:37 pm EDT.
Sunshine
The average sunshine in September in Darien is 8.8h.UV index
In Darien, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: The UV index of 4 during September leads to these advisories:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Boost your sun resistance with garments that are densely woven yet spacious.
Frequently asked questions
What is the usual temperature for Darien in September?
What is the average humidity in September in Darien?
How many days does it rain in September in Darien?
When it does not snow in Darien?
What is the average length of the day in September in Darien?
What time are sunrise and sunset in September in Darien?
How many hours of sunshine does Darien have in September?
How high is the UV index in September in Darien?
Average temperature in September
Darien, CT
- Average high temperature in September: 73.2°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (36.1°F).
- Average low temperature in September: 62.1°F
The month with the highest average low temperature is July (68.9°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).
Average pressure in September
Darien, CT
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Darien, CT
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest month (with the lowest average wind speed) is July (6.6mph).
Average humidity in September
Darien, CT
- Average humidity in September: 74%
The month with the highest relative humidity is May (76%).
The months with the lowest relative humidity are April, August and November (72%).
Average rainfall in September
Darien, CT
- Average rainfall in September: 2.76"
The wettest months (with the highest rainfall) are July and December (4.17").
The driest month (with the least rainfall) is January (2.48").
Average rainfall days in September
Darien, CT
- Average rainfall days in September: 13.1 days
The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is January (8.8 days).
Average snowfall in September
Darien, CT
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.64").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Darien, CT
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (7.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Darien, CT
- Average daylight in September: 12h and 3min
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 5min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 36min).
Average sunshine days in September
Darien, CT
- Average sunshine days in September: 14.7 days
The month with the most sunshine days is November (17.3 days).
The month with the least sunshine days is June (10.8 days).
Average UV index in September
Darien, CT
- 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
Darien, CT
- Average cloud cover in September: 35
The month with the most cloud cover is December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Darien, CT
- 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).
Darien, Connecticut, USA
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