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 sea temperature 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
As August makes way for September, Port Jefferson's average high-temperature eases from a warm 78.4°F (25.8°C) to a pleasant 72.3°F (22.4°C). Throughout September, Port Jefferson's nights experience a slight temperature dip to a comfortable 64.8°F (18.2°C).Humidity
In Port Jefferson, the average relative humidity in September is 74%.Rainfall
In Port Jefferson, in September, it is raining for 12.6 days, with typically 2.4" (61mm) of accumulated precipitation. Throughout the year, in Port Jefferson, there are 146.8 rainfall days, and 33.78" (858mm) of precipitation is accumulated.Snowfall
In Port Jefferson, snow does not fall in April through September.Ocean temperature
In September, the average ocean temperature is 69.6°F (20.9°C).Note: The majority of individuals find it unpleasurable to swim in 69.6°F (20.9°C). It becomes progressively harder to manage one's breathing as the water temperature falls below 69.8°F (21°C).
Daylight
In September, the average length of the day is 12h and 28min.On the first day of September in Port Jefferson, sunrise is at 6:19 am and sunset at 7:24 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:35 pm EDT.
Sunshine
The average sunshine in September in Port Jefferson, New York, is 8.9h.UV index
In Port Jefferson, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: The daily high UV index of 5 during September translates into the following recommendations:
Put precautions into practice - Protective measures against sun-induced damage are advised. Minimize direct exposure to the Sun during midday when its radiation is at its peak. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
Frequently asked questions
What is the temperature in September in Port Jefferson?
What is the average humidity in September in Port Jefferson?
How many days does it rain in September in Port Jefferson?
When it does not snow in Port Jefferson?
Does it snow in Port Jefferson in September?
How cold is the water in September in Port Jefferson?
How many hours of daylight does Port Jefferson have in September?
When are sunrise and sunset in September in Port Jefferson?
How long on average sun shines in September in Port Jefferson?
What is the UV index intensity in September in Port Jefferson?
Average temperature in September
Port Jefferson, NY
- Average high temperature in September: 72.3°F
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is January (37.6°F).
- Average low temperature in September: 64.8°F
The months with the highest average low temperature are July and August (71.1°F).
The coldest month (with the lowest average low temperature) is January (29.1°F).
Average pressure in September
Port Jefferson, NY
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Port Jefferson, NY
- Average wind speed in September: 9.8mph
The windiest month (with the highest average wind speed) is January (12.9mph).
The calmest month (with the lowest average wind speed) is July (8.3mph).
Average humidity in September
Port Jefferson, NY
- Average humidity in September: 74%
The months with the highest relative humidity are May and June (77%).
The month with the lowest relative humidity is November (71%).
Average rainfall in September
Port Jefferson, NY
- Average rainfall in September: 2.4"
The wettest month (with the highest rainfall) is December (3.58").
The driest month (with the least rainfall) is January (2.05").
Average rainfall days in September
Port Jefferson, NY
- Average rainfall days in September: 12.6 days
The month with the highest number of rainy days is July (16.5 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in September
Port Jefferson, NY
- Average snowfall in September: 0"
The month with the highest snowfall is March (2.13").
The months with the least snowfall are April, May, June, July, August and September (0").
Average snowfall days in September
Port Jefferson, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average sea temperature in September
Port Jefferson, NY
- Average sea temperature in September: 69.6°F
The best month for swimming (with the highest average sea temperature) is August (74°F).
The coldest month (with the lowest average sea temperature) is February (39.7°F).
Average daylight in September /
Average sunshine in September
Port Jefferson, NY
- 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 36min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in September
Port Jefferson, NY
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is November (20.5 days).
The month with the least sunshine days is July (13 days).
Average UV index in September
Port Jefferson, NY
- Average UV index in September: 5
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
Port Jefferson, NY
- Average cloud cover in September: 33
The month with the most cloud cover is December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Port Jefferson, NY
- 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).
Port Jefferson, New York, USA
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