September weather forecastMystic, CT
September
Weather in September
September bids goodbye to summer with a notable decrease in temperature scale. The average high drops to 71.4°F (21.9°C), a perfect transition from the hot summer towards the cooler autumn. As autumn colors start to show, the city of Mystic transforms into an artist's palette with hues of gold, orange, and red. The month's climatic conditions with its comfortable warmth during the day and cooler evenings make it a favored time for visitors. Enjoy walking tours through the splendid historic sites or boat tours appreciating the onset of the beautiful fall foliage.Temperature
September witnesses a gentle descent in average high-temperature, descending from August's moderately hot 77.7°F (25.4°C) to a pleasant 71.4°F (21.9°C). Throughout September, an average low-temperature of 59.9°F (15.5°C) is expected.Humidity
In September, the average relative humidity is 78%.Rainfall
The month with the least rainfall is September, when the rain falls for 12.8 days and typically collects 1.73" (44mm) of precipitation.Snowfall
May through September are months without snowfall.Ocean temperature
In Mystic, the average seawater temperature in September is 67.6°F (19.8°C).Note: Most people do not find swimming enjoyable in water of 67.6°F (19.8°C). The task of controlling breathing becomes tougher as the temperature drops from 69.8°F (21°C) to 59°F (15°C).
Daylight
In Mystic, Connecticut, the average length of the day in September is 12h and 28min.On the first day of September in Mystic, sunrise is at 6:14 am and sunset at 7:20 pm. On the last day of the month, sunrise is at 6:44 am and sunset at 6:30 pm EDT.
Sunshine
The average sunshine in September in Mystic is 8.9h.UV index
The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.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. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Mystic, CT
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is July (77.9°F).
The month with the lowest average high temperature is January (36.5°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (26.6°F).
Average pressure in September
Mystic, 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
Mystic, CT
- Average wind speed in September: 9.2mph
The windiest month (with the highest average wind speed) is January (12.4mph).
The calmest month (with the lowest average wind speed) is August (8.1mph).
Average humidity in September
Mystic, CT
- Average humidity in September: 78%
The month with the highest relative humidity is June (81%).
The months with the lowest relative humidity are January, March, April and November (74%).
Average rainfall in September
Mystic, CT
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is December (3.86").
The driest month (with the least rainfall) is September (1.73").
Average rainfall days in September
Mystic, CT
- Average rainfall days in September: 12.8 days
The month with the highest number of rainy days is July (17.1 days).
The month with the least rainy days is February (10.1 days).
Average snowfall in September
Mystic, CT
- Average snowfall in September: 0"
The month with the highest snowfall is March (2.44").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Mystic, CT
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.8 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in September
Mystic, CT
- Average sea temperature in September: 67.6°F
The best month for swimming (with the highest average sea temperature) is August (70.3°F).
The coldest month (with the lowest average sea temperature) is February (37.9°F).
Average daylight in September /
Average sunshine in September
Mystic, CT
- Average daylight in September: 12h and 30min
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 12min).
- Average sunshine in September: 8h and 54min
The month with the most sunshine is August (Average sunshine: 10h and 36min).
The months with the least sunshine are February and December (Average sunshine: 4h and 54min).
Average sunshine days in September
Mystic, CT
- Average sunshine days in September: 15.2 days
The month with the most sunshine days is November (16.5 days).
The months with the least sunshine days are June and July (11.7 days).
Average UV index in September
Mystic, 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 and December (UV index 2).
Average cloud cover in September
Mystic, CT
- Average cloud cover in September: 32
The months with the most cloud cover are February, March and December (Cloud cover 47).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Mystic, 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).
