September weather forecastGreat River, NY
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Great River, New York, with an average temperature varying between 65.3°F (18.5°C) and 72.1°F (22.3°C).Temperature
The transition into September involves a small decrease in the average high-temperature, dipping slightly from a warm 78.1°F (25.6°C) in August to an agreeable 72.1°F (22.3°C). Great River notes a steady average temperature of 65.3°F (18.5°C) during the nights of September.Humidity
The average relative humidity in September is 74%.Rainfall
In September, the rain falls for 12.8 days. Throughout September, 2.48" (63mm) of precipitation is accumulated. Throughout the year, there are 155.3 rainfall days, and 34.84" (885mm) of precipitation is accumulated.Snowfall
April, June through September and November are months without snowfall.Ocean temperature
In Great River, the average seawater temperature in September is 69.6°F (20.9°C).Note: The majority find it unenjoyable to swim in 69.6°F (20.9°C). Breathing becomes tougher as the water temperature descends under 69.8°F (21°C).
Daylight
In September, the average length of the day is 12h and 27min.On the first day of the month, sunrise is at 6:20 am and sunset at 7:24 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:35 pm EDT.
Sunshine
In September, the average sunshine is 9.2h.UV index
In Great River, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: In September, a regular UV index of 5 translates into these guidelines:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Stay sun-safe with clothing that is both closely woven and worn loosely.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Great River, NY
- Average high temperature in September: 72.1°F
The warmest month (with the highest average high temperature) is August (78.1°F).
The month with the lowest average high temperature is January (37.9°F).
- Average low temperature in September: 65.3°F
The month with the highest average low temperature is August (71.8°F).
The coldest month (with the lowest average low temperature) is January (30.2°F).
Average pressure in September
Great River, 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
Great River, NY
- Average wind speed in September: 10.4mph
The windiest month (with the highest average wind speed) is January (13.8mph).
The calmest months (with the lowest average wind speed) are July and August (9mph).
Average humidity in September
Great River, NY
- Average humidity in September: 74%
The months with the highest relative humidity are May and June (78%).
The month with the lowest relative humidity is November (71%).
Average rainfall in September
Great River, NY
- Average rainfall in September: 2.48"
The wettest month (with the highest rainfall) is December (3.74").
The driest month (with the least rainfall) is January (2.17").
Average rainfall days in September
Great River, NY
- Average rainfall days in September: 12.8 days
The month with the highest number of rainy days is July (17.7 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in September
Great River, NY
- Average snowfall in September: 0"
The month with the highest snowfall is March (2.13").
The months with the least snowfall are April, June, July, August, September and November (0").
Average snowfall days in September
Great River, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average sea temperature in September
Great River, 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
Great River, NY
- Average daylight in September: 12h and 30min
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 18min).
- Average sunshine in September: 9h and 12min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Great River, NY
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is November (18.8 days).
The month with the least sunshine days is July (11.3 days).
Average UV index in September
Great River, 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 and December (UV index 2).
Average cloud cover in September
Great River, NY
- Average cloud cover in September: 31
The month with the most cloud cover is December (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Great River, 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).





