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
With the beginning of September, the average high-temperature shows a small decrease, transitioning from a warm 78.4°F (25.8°C) in August to an agreeable 72.1°F (22.3°C). During September, South Lyme witnesses a consistent average low-temperature of 59.7°F (15.4°C).Humidity
In September, the average relative humidity in South Lyme, Connecticut, is 77%.Rainfall
September is the month with the least rainfall in South Lyme. Rain falls for 9.1 days and accumulates 0.35" (9mm) of precipitation.Snowfall
In South Lyme, snow does not fall in April through October.Daylight
In September, the average length of the day in South Lyme is 12h and 28min.On the first day of the month, sunrise is at 6:16 am and sunset at 7:21 pm. On the last day of September, in South Lyme, sunrise is at 6:45 am and sunset at 6:32 pm EDT.
Sunshine
In South Lyme, the average sunshine in September is 8.9h.UV index
The average daily maximum UV index in September in South Lyme 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:
Undertake precautions - It is suggested to shield oneself from sunburn. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Frequently asked questions
What is the average September temperature in South Lyme?
What is the average humidity in September in South Lyme?
What is the driest month in South Lyme?
How many days does it rain in September in South Lyme?
When it does not snow in South Lyme?
How many hours of daylight does South Lyme have in September?
What time are sunrise and sunset in September in South Lyme?
How many hours of sunshine does South Lyme have in September?
What is the UV index reading in September in South Lyme?
Average temperature in September
South Lyme, CT
- Average high temperature in September: 72.1°F
The warmest month (with the highest average high temperature) is July (79.5°F).
The month with the lowest average high temperature is January (35.4°F).
- Average low temperature in September: 59.7°F
The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).
Average pressure in September
South Lyme, CT
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
South Lyme, CT
- Average wind speed in September: 8.1mph
The windiest month (with the highest average wind speed) is January (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.2mph).
Average humidity in September
South Lyme, CT
- Average humidity in September: 77%
The months with the highest relative humidity are June and July (79%).
The month with the lowest relative humidity is April (73%).
Average rainfall in September
South Lyme, CT
- Average rainfall in September: 0.35"
The wettest month (with the highest rainfall) is December (0.94").
The driest month (with the least rainfall) is September (0.35").
Average rainfall days in September
South Lyme, CT
- Average rainfall days in September: 9.1 days
The month with the highest number of rainy days is July (11.5 days).
The months with the least rainy days are February and November (6.6 days).
Average snowfall in September
South Lyme, CT
- Average snowfall in September: 0"
The month with the highest snowfall is March (0.63").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
South Lyme, CT
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.4 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
South Lyme, 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 months with the most sunshine are July and August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 48min).
Average sunshine days in September
South Lyme, CT
- Average sunshine days in September: 19.3 days
The month with the most sunshine days is November (21.1 days).
The month with the least sunshine days is July (15.8 days).
Average UV index in September
South Lyme, 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
South Lyme, CT
- Average cloud cover in September: 33
The months with the most cloud cover are February and December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
South Lyme, 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).
South Lyme, Connecticut, USA
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