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
A subtle shift in Old Lyme's weather is observed as August turns into September, with the average high temperature reducing from a warm 78.4°F (25.8°C) to a pleasant 72.1°F (22.3°C). Old Lyme, in September, observes a steady average low-temperature of 59.7°F (15.4°C).Humidity
The average relative humidity in September is 77%.Rainfall
The month with the least rainfall is September, when the rain falls for 9.1 days and typically collects 0.35" (9mm) of precipitation.Snowfall
In Old Lyme, snow does not fall in April through October.Daylight
In Old Lyme, the average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:16 am and sunset at 7:21 pm. On the last day of the month, sunrise is at 6:45 am and sunset at 6:32 pm EDT.
Sunshine
In September, the average sunshine is 8.9h.UV index
In September, the average daily maximum UV index 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: In September, the average maximum UV index of 4 translates into the following recommendations:
Adopt protective measures - Suggestions to resist sunburn are offered. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
What is the driest month?
How much does it rain in September?
When it does not snow?
What is the average length of the day in September?
What time are sunrise and sunset in September in Old Lyme?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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
Old 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).
Old Lyme, Connecticut, USA
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