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
September marks a gentle change in average high-temperature, declining from August's moderately hot 79.2°F (26.2°C) to an agreeable 71.4°F (21.9°C). During September, Rotterdam records an average temperature of 51.6°F (10.9°C) at night.Humidity
The average relative humidity in September is 78%.Rainfall
In September, the rain falls for 10.1 days. Throughout September, 1.73" (44mm) of precipitation is accumulated. Throughout the year, there are 137.4 rainfall days, and 25.75" (654mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 29min.On the first day of September, sunrise is at 6:21 am and sunset at 7:29 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:38 pm EDT.
Sunshine
In September, the average sunshine is 9h.UV index
The average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: A daily high UV index of 3 in September leads to these guidelines:
Ensure safety - Sun damage prevention is strongly urged. To guard against the harmful effects of the Sun, minimize exposure during midday. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Rotterdam have in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Rotterdam have in September?
How high is the UV index in September in Rotterdam?
Average temperature in September
Rotterdam, NY
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (28.6°F).
- Average low temperature in September: 51.6°F
The month with the highest average low temperature is July (59.7°F).
The coldest month (with the lowest average low temperature) is January (16.9°F).
Average pressure in September
Rotterdam, NY
- Average pressure in September: 30.06"Hg
The month with the highest atmospheric pressure is November (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Rotterdam, NY
- Average wind speed in September: 5.5mph
The windiest month (with the highest average wind speed) is January (8mph).
The calmest month (with the lowest average wind speed) is August (5.2mph).
Average humidity in September
Rotterdam, NY
- Average humidity in September: 78%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is April (74%).
Average rainfall in September
Rotterdam, NY
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is January (1.57").
Average rainfall days in September
Rotterdam, NY
- Average rainfall days in September: 10.1 days
The month with the highest number of rainy days is May (16 days).
The month with the least rainy days is January (6.2 days).
Average snowfall in September
Rotterdam, NY
- Average snowfall in September: 0"
The month with the highest snowfall is February (6.02").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Rotterdam, NY
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (9.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Rotterdam, NY
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 3h and 48min).
Average sunshine days in September
Rotterdam, NY
- Average sunshine days in September: 17.9 days
The month with the most sunshine days is January (19.3 days).
The month with the least sunshine days is April (12.6 days).
Average UV index in September
Rotterdam, NY
- Average UV index in September: 3
The months with the highest UV index are May, June, July and August (UV index 5).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Rotterdam, NY
- Average cloud cover in September: 35
The month with the most cloud cover is February (Cloud cover 58).
The months with the least cloud cover are July and August (Cloud cover 32).
Average visibility in September
Rotterdam, NY
- Average visibility in September: 5mi
The months with the highest visibility are April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are January, February, March, May and September (5mi).
Rotterdam, New York, USA
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