September weather forecast
Jamestown, RI

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Weather in September

September casts a unique spell over Jamestown, marking the transition from the dog days of summer to the crisp arrival of fall. The winds begin to pick up, bearing the aroma of changing leaves and the promise of the harvest season ahead. While the average high temperature recedes to a comfortable 71.4°F, the sea remains warm at 67.2°F, thus resulting in pleasant beach conditions. The month encapsulates both summer's farewell and autumn's welcome, striking a peaceful balance between the two. September paints a colorful portrait of Jamestown - one of shifting seasons, gradual change, and anticipation for the spectacle of fall that is to come.

Temperature

September brings a minor shift in the average high-temperature, adjusting from a moderately hot 77.7°F in August to an agreeable 71.4°F. In September, Jamestown records an average nighttime temperature of 59.7°F.

Humidity

The average relative humidity in September in Jamestown is 78%.

Rainfall

September is the month with the least rainfall. Rain falls for 11.6 days and accumulates 1.42" of precipitation.

Snowfall

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

Ocean temperature

In Jamestown, the average seawater temperature in September is 67.3°F.
Note: Swimming is not enjoyable for most people in water that is 67.3°F. As the temperature descends from 69.8°F to 59°F, breathing control becomes harder.

Daylight

The average length of the day in September in Jamestown is 12h and 28min.
On the first day of the month, sunrise is at 6:11 am and sunset at 7:19 pm. On the last day of September, in Jamestown, Rhode Island, sunrise is at 6:41 am and sunset at 6:29 pm EDT.

Sunshine

In September, the average sunshine is 8.7h.

UV index

In Jamestown, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for average individuals.
Note: In September, a regular UV index of 4 translates into these guidelines:
Make use of precautions - Suggestions to resist sunburn are communicated. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
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FAQ

What are September temperatures in Jamestown?

The high-temperature, in September, in Jamestown, is 71.4°F, while the low-temperature averages to 59.7°F.

What is the average humidity in September in Jamestown?

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

What is the driest month in Jamestown?

The month with the least rainfall in Jamestown, Rhode Island, is September, when the rain falls for 11.6 days and typically collects 1.42" of precipitation.

How many days does it rain in September in Jamestown?

In September, in Jamestown, Rhode Island, the rain falls for 11.6 days. Throughout September, 1.42" of precipitation is accumulated.

When it does not snow in Jamestown?

April, June through October are months without snowfall in Jamestown.

What is the ocean temperature in September in Jamestown?

In September, the average ocean temperature in Jamestown is 67.3°F. For most, swimming in 67.3°F is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F to 59°F.

How many hours of daylight does Jamestown have in September?

In September, the average day length is 12h and 28min.

When is the sunrise / sunset in September in Jamestown?

On the first day of September in Jamestown, sunrise is at 6:11 am and sunset at 7:19 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:29 pm EDT.

How many hours of sunshine does Jamestown have in September?

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

How high is the UV index in September in Jamestown?

In Jamestown, Rhode Island, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.
Today
Tomorrow
Long-term
YearJFMAMJJASeptemberOND
Aug
September
Oct
Average high temperature
77.7°F
71.4°F
61.7°F
Average low temperature
65.7°F
59.7°F
51.3°F
Average pressure
29.98"Hg
30.05"Hg
30.01"Hg
Average wind speed
8.1mph
9mph
10.6mph
Average max. wind speed
8.8mph
9.4mph
11.4mph
Average wind speed gusts
12.9mph
14.1mph
16.8mph
Average humidity
78%
78%
76%
Average rainfall
2.09"
1.42"
3.27"
Average rainfall days
11.8
11.6
13.4
Average snowfall
0"
0"
0"
Average snowfall days
0
0
0
Average sea temperature
69.6°F
67.2°F
62.2°F
Average daylight
13h 5min
12h 3min
11h 1min
Average sunshine
10h 3min
8h 4min
6h 2min
Average sunshine days
16.9
15.8
15.1
Average UV index
6
4
3
Average cloud cover
29%
33%
41%
Average visibility
6mi
6mi
6mi

Average temperature in September
Jamestown, RI

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).

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Average pressure in September
Jamestown, RI

Average pressure in September - Jamestown, RI
  • Average pressure in September: 30.05"Hg

The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

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Average wind speed in September
Jamestown, RI

Average wind speed in September - Jamestown, RI
  • Average wind speed in September: 9mph

The windiest month (with the highest average wind speed) is January (12.1mph).
The calmest month (with the lowest average wind speed) is August (8.1mph).

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Average humidity in September
Jamestown, RI

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%).

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Average rainfall in September
Jamestown, RI

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 least rainfall) is September (1.42").

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Average rainfall days in September
Jamestown, RI

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 least rainy days is January (8.3 days).

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Average snowfall in September
Jamestown, RI

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

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

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Average snowfall days in September
Jamestown, RI

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).
The months with the least snowfall days are June, July, August, September and October (0 days).

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Average sea temperature in September
Jamestown, RI

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).

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Average daylight in September /
Average sunshine in September
Jamestown, RI

Average daylight in September / Average sunshine in September - Jamestown, RI
  • 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 12min).

  • Average sunshine in September: 8h and 4min

The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).

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Average sunshine days in September
Jamestown, RI

Average sunshine days in September - Jamestown, RI
  • Average sunshine days in September: 15.8 days

The month with the most sunshine days is November (17.7 days).
The month with the least sunshine days is April (12.3 days).

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Average UV index in September
Jamestown, RI

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

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).

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Average cloud cover in September
Jamestown, RI

Average cloud cover in September - Jamestown, RI
  • Average cloud cover in September: 33

The month with the most cloud cover is March (Cloud cover 48).
The month with the least cloud cover is August (Cloud cover 29).

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Average visibility in September
Jamestown, RI

Average visibility in September - Jamestown, RI
  • 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).

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Jamestown, Rhode Island, USA

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