September weather forecastPort Jefferson, OH
September
Weather in September
The first month of the autumn, September, is still a warm month in Port Jefferson, Ohio, with an average temperature ranging between min 56.1°F (13.4°C) and max 73.6°F (23.1°C).Temperature
The shift from August to September includes a minor decrease in the average high-temperature, lightly dropping from 79.2°F (26.2°C) to a still warm 73.6°F (23.1°C). An average low-temperature of 56.1°F (13.4°C) is common during the nights of September.Humidity
In September, the average relative humidity is 79%.Rainfall
In Port Jefferson, in September, it is raining for 10.3 days, with typically 0.51" (13mm) of accumulated precipitation. Throughout the year, there are 111.7 rainfall days, and 8.58" (218mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 27min.On the first day of the month, sunrise is at 7:04 am and sunset at 8:07 pm. On the last day of September, sunrise is at 7:32 am and sunset at 7:19 pm EDT.
Sunshine
In Port Jefferson, the average sunshine in September is 8.1h.UV index
In Port Jefferson, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for ordinary individuals.Note: A maximum UV index of 4 in September translates into the following recommendations:
Be mindful. Individuals with a lighter skin tone may suffer burns in less than 30 minutes. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Port Jefferson, OH
- Average high temperature in September: 73.6°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (32°F).
- Average low temperature in September: 56.1°F
The month with the highest average low temperature is July (63.7°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).
Average pressure in September
Port Jefferson, OH
- Average pressure in September: 30.04"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Port Jefferson, OH
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is January (10.6mph).
The calmest month (with the lowest average wind speed) is August (5.8mph).
Average humidity in September
Port Jefferson, OH
- Average humidity in September: 79%
The months with the highest relative humidity are January, February and December (83%).
The month with the lowest relative humidity is October (75%).
Average rainfall in September
Port Jefferson, OH
- Average rainfall in September: 0.51"
The wettest months (with the highest rainfall) are May and June (1.06").
The driest month (with the least rainfall) is November (0.47").
Average rainfall days in September
Port Jefferson, OH
- Average rainfall days in September: 10.3 days
The month with the highest number of rainy days is May (13.2 days).
The month with the least rainy days is February (5 days).
Average snowfall in September
Port Jefferson, OH
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.79").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Port Jefferson, OH
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Port Jefferson, OH
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 8h and 6min
The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
Port Jefferson, OH
- Average sunshine days in September: 17.2 days
The month with the most sunshine days is November (21.8 days).
The month with the least sunshine days is July (13.6 days).
Average UV index in September
Port Jefferson, OH
- 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, October, November and December (UV index 2).
Average cloud cover in September
Port Jefferson, OH
- Average cloud cover in September: 35
The month with the most cloud cover is January (Cloud cover 64).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Port Jefferson, OH
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, May, June, July, October, November and December (6mi).
The months with the lowest visibility are August and September (5mi).





