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
Start of September brings a slight shift in the average high-temperature, dipping a bit from August's moderately hot 77.5°F (25.3°C) to a pleasant 71.2°F (21.8°C). The September nights in Riverhead show a slight decrease to a mean low-temperature of 65.1°F (18.4°C).Humidity
The average relative humidity in September in Riverhead is 75%.Rainfall
The month with the least rainfall is September, when the rain falls for 12.3 days and typically collects 1.89" (48mm) of precipitation.Snowfall
April, June through October are months without snowfall in Riverhead, New York.Daylight
The average length of the day in September is 12h and 27min.On the first day of the month, sunrise is at 6:18 am and sunset at 7:22 pm. On the last day of September, sunrise is at 6:46 am and sunset at 6:33 pm EDT.
Sunshine
In Riverhead, the average sunshine in September is 9h.UV index
In Riverhead, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: In September, an average UV index of 5 transforms into the following instructions:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. Around midday, solar radiation is most harmful; hence, exposure should be limited. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Frequently asked questions
What is the average September temperature in Riverhead?
What is the average humidity in September in Riverhead?
What is the driest month in Riverhead?
How much does it rain in Riverhead in September?
When it does not snow in Riverhead?
How many hours of daylight does Riverhead have in September?
When is the sunrise / sunset in September in Riverhead?
How many hours of sunshine does Riverhead have in September?
How high is the UV index in September in Riverhead?
Average temperature in September
Riverhead, NY
- Average high temperature in September: 71.2°F
The warmest month (with the highest average high temperature) is August (77.5°F).
The month with the lowest average high temperature is January (38.7°F).
- Average low temperature in September: 65.1°F
The month with the highest average low temperature is August (71.2°F).
The coldest month (with the lowest average low temperature) is January (30.6°F).
Average pressure in September
Riverhead, 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
Riverhead, NY
- Average wind speed in September: 11.2mph
The windiest month (with the highest average wind speed) is January (14.5mph).
The calmest month (with the lowest average wind speed) is July (9.5mph).
Average humidity in September
Riverhead, NY
- Average humidity in September: 75%
The month with the highest relative humidity is May (80%).
The month with the lowest relative humidity is November (71%).
Average rainfall in September
Riverhead, NY
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is December (3.27").
The driest month (with the least rainfall) is September (1.89").
Average rainfall days in September
Riverhead, NY
- Average rainfall days in September: 12.3 days
The month with the highest number of rainy days is July (15.6 days).
The month with the least rainy days is February (9 days).
Average snowfall in September
Riverhead, NY
- Average snowfall in September: 0"
The month with the highest snowfall is March (1.54").
The months with the least snowfall are April, June, July, August, September and October (0").
Average snowfall days in September
Riverhead, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.5 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
Riverhead, 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: 9h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 42min).
Average sunshine days in September
Riverhead, NY
- Average sunshine days in September: 15.7 days
The month with the most sunshine days is November (17.5 days).
The month with the least sunshine days is February (13.2 days).
Average UV index in September
Riverhead, 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
Riverhead, NY
- Average cloud cover in September: 31
The month with the most cloud cover is December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Riverhead, 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).
Riverhead, New York, USA
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