September weather forecast
Chatham, NY

Weather in September

The first month of the autumn, September, is still a pleasant month in Chatham, New York, with average temperature fluctuating between 51.1°F (10.6°C) and 71.2°F (21.8°C).

Temperature

In September, the average high-temperature marginally drops, from a moderately hot 78.8°F (26°C) in August, to a pleasant 71.2°F (21.8°C). In September, in Chatham, the average low-temperature is 51.1°F (10.6°C).

Humidity

The average relative humidity is 79%.

Rainfall

In Chatham, New York,, it is raining for 10.7 days, with typically 1.57" (40mm) of accumulated precipitation. Throughout the year, there are 135.1 rainfall days, and 20.39" (518mm) of precipitation is accumulated.

Snowfall

June through September are months without snowfall in Chatham, New York.

Daylight

In Chatham, the average length of the day is 12.5h.

Sunshine

In Chatham, the average sunshine is 8.8h.

UV index

In September, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from the exposure to the Sun's UV radiation for ordinary individuals.
Note: The average daily UV index of 3 in September transform into the following instructions:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in September in Chatham?

In Chatham, New York, the average relative humidity in September is 79%.

How many days does it rain in September in Chatham?

In Chatham, in September, during 10.7 rainfall days, 1.57" (40mm) of precipitation is typically accumulated.

When it does not snow in Chatham?

June through September are months without snowfall.

Does it snow in Chatham in September?

In Chatham, New York, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Chatham have in September?

In September, the average length of the day is 12.5h.

How many hours of sunshine does Chatham have in September?

In September, the average sunshine in Chatham, New York, is 8.8h.

How high is the UV index in September in Chatham?

In September, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a medium health risk from the exposure to the Sun's UV rays.

Average temperature in September
Chatham, NY

Average temperature in September - Chatham, NY
  • Average high temperature in September: 71.2°F

The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is January (29.1°F).

  • Average low temperature in September: 51.1°F

The month with the highest average low temperature is July (59°F).
The coldest month (with the lowest average low temperature) is January (16.7°F).

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Average pressure in September
Chatham, NY

Average pressure in September - Chatham, NY
  • Average pressure in September: 30.06"

The month with the highest atmospheric pressure is November (30.09").
The month with the lowest atmospheric pressure is June (29.92").

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Average wind speed in September
Chatham, NY

Average wind speed in September - Chatham, NY
  • Average wind speed in September: 5.5mph

The windiest months (with the highest average wind speed) are January and March (8.2mph).
The calmest month (with the lowest average wind speed) is August (5mph).

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Average humidity in September
Chatham, NY

Average humidity in September - Chatham, NY
  • Average humidity in September: 79%

Months with the highest relative humidity are February and December (83%).
The month with the lowest relative humidity is April (75%).

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Average rainfall in September
Chatham, NY

Average rainfall in September - Chatham, NY
  • Average rainfall in September: 1.57"

The wettest month (with the highest rainfall) is July (2.4").
The driest month (with the least rainfall) is January (1.1").

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Average rainfall days in September
Chatham, NY

Average rainfall days in September - Chatham, NY
  • Average rainfall days in September: 10.7 days

The month with the highest number of rainy days is May (15.8 days).
The month with the least rainy days is January (5.7 days).

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Average snowfall in September
Chatham, NY

Average snowfall in September - Chatham, NY
  • Average snowfall in September: 0"

The month with the highest snowfall is March (3.9").
Months with the least snowfall are June, July, August and September (0").

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Average snowfall days in September
Chatham, NY

Average snowfall days in September - Chatham, NY
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (9.3 days).
Months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in September /
Average sunshine in September
Chatham, NY

Average daylight in September / Average sunshine in September - Chatham, NY
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.2h).
The month with the shortest days is December (Average daylight: 9.1h).

  • Average sunshine in September: 8.8h

Months with the most sunshine are July and August (Average sunshine: 10.3h).
The month with the least sunshine is February (Average sunshine: 3.8h).

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Average sunshine days in September
Chatham, NY

Average sunshine days in September - Chatham, NY
  • Average sunshine days in September: 16.7 days

The month with the most sunshine days is January (20 days).
The month with the least sunshine days is June (12.5 days).

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Average UV index in September
Chatham, NY

Average UV index in September - Chatham, NY
  • Average UV index in September: 3

Months with the highest UV index are May, June, July and August (UV index 5).
Months with the lowest UV index are January, February, March, November and December (UV index 2).

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Average cloud cover in September
Chatham, NY

Average cloud cover in September - Chatham, NY
  • Average cloud cover in September: 38

The month with the most cloud cover is February (Cloud cover 58).
Months with the least cloud cover are July and August (Cloud cover 35).

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Average visibility in September
Chatham, NY

Average visibility in September - Chatham, NY
  • Average visibility in September: 5mi

Months with the highest visibility are January, April, November and December (6mi).
Months with the lowest visibility are February, March, May, June, July, August, September and October (5mi).

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