Jamestown
Rhode Island, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Jamestown, RI

September, the first month of the autumn, in Jamestown, is also an agreeable month, with temperature in the range of an average low of 59.7°F (15.4°C) and an average high of 71.4°F (21.9°C).

Temperature

In September, the average high-temperature marginally drops, from a moderately hot 77.7°F (25.4°C) in August, to a pleasant 71.4°F (21.9°C). The average low-temperature, in September, is 59.7°F (15.4°C).

Humidity

In Jamestown, the average relative humidity is 78%.

Rainfall

The month with the least rainfall is September when the rain falls for 11.6 days and typically collects 1.42" (36mm) of precipitation.

Snowfall

In Jamestown snow does not fall in April, June through October.

Ocean temperature

In September, the average ocean temperature in Jamestown is 67.3°F (19.6°C).
Note: Swimming in 67.3°F (19.6°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

Daylight

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

Sunshine

In September, the average sunshine is 8.7h.

UV index

The average daily maximum UV index in Jamestown is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to the Sun's UV rays for the average person.
Note: In September, the average maximum UV index of 4 translate into the following recommendations:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.

What is the temperature in September in Jamestown?

In September, in Jamestown, Rhode Island, the average high-temperature is 71.4°F (21.9°C), and the average low-temperature is 59.7°F (15.4°C).

What is the average humidity in September in Jamestown?

In September, the average relative humidity in Jamestown, Rhode Island, is 78%.

How many days does it rain in September in Jamestown?

In Jamestown, in September, during 11.6 rainfall days, 1.42" (36mm) of precipitation is typically accumulated.

What is the driest month in Jamestown?

The month with the least rainfall in Jamestown is September when the rain falls for 11.6 days and typically collects 1.42" (36mm) of precipitation.

When it does not snow in Jamestown?

In Jamestown, Rhode Island, snow does not fall in April, June through October.

What is the ocean temperature in September in Jamestown?

In Jamestown, the average seawater temperature in September is 67.3°F (19.6°C). Swimming in 67.3°F (19.6°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

How many hours of daylight does Jamestown have in September?

The average length of the day in September in Jamestown is 12.5h.

How long on average sun shines in September in Jamestown?

In Jamestown, Rhode Island, the average sunshine in September is 8.7h.

What is the UV index reading in September in Jamestown?

The average daily maximum UV index in September in Jamestown, Rhode Island, is 4. A UV Index estimate of 3 to 5 represents a moderate vulnerability from the exposure to the Sun's UV rays.
Average temperature in September - Jamestown, RI
  • Average high temperature in September: 71.4°F

The warmest month (with the highest average high temperature) is July (78.3°F).
The month with the lowest average high temperature is January (36.1°F).

  • Average low temperature in September: 59.7°F

The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).

Average humidity in September - Jamestown, RI
  • Average humidity in September: 78%

The month with the highest relative humidity is June (81%).
The month with the lowest relative humidity is March (73%).

Average rainfall in September - Jamestown, RI
  • Average rainfall in September: 1.42"

The wettest month (with the highest rainfall) is October (3.27").
The driest month (with the lowest rainfall) is September (1.42").

Average rainfall days in September - Jamestown, RI
  • Average rainfall days in September: 11.6 days

The month with the highest number of rainy days is April (15.6 days).
The month with the lowest number of rainy days is January (8.3 days).

Average snowfall in September - Jamestown, RI
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.76").
Months with the lowest snowfall are April, June, July, August, September and October (0").

Average snowfall days in September - Jamestown, RI
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (6.6 days).
Months with the lowest number of snowfall days are June, July, August, September and October (0 days).

Average sea temperature in September - Jamestown, RI
  • Average sea temperature in September: 67.2°F

The best month for swimming (with the highest average sea temperature) is August (69.6°F).
The coldest month (with the lowest average sea temperature) is February (38.1°F).

Average daylight in September / Average sunshine in September - Jamestown, RI
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.1h).
The month with shortest days is December (Average daylight: 9.2h).

  • Average sunshine in September: 8.7h

The month with most sunshine is August (Average sunshine: 10.5h).
The month with least sunshine is February (Average sunshine: 4.8h).

Average UV index in September - Jamestown, RI
  • Average UV index in September: 4

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, March and December (UV index 2).