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September Weather in Jamestown, United States

Last updated: June 24, 2025

In September, the average temperature in Jamestown, United States hovers around 19°C (66°F), with minimums dipping to 3°C (39°F) and maximums soaring up to 33°C (91°F). During this time, expect 100 mm (3.9 in) of precipitation over approximately 10 days. Additionally, the average humidity remains comfortably high at 77%, making for a uniquely vibrant atmosphere.

September Temperature in Jamestown

In September in Jamestown, the average temperature is 19°C (66°F). Maximum temperatures can reach 33°C (91°F), while the minimum can drop as low as 3°C (39°F). Be prepared for both warm days and cooler nights when planning your trip!

September Weather in Jamestown: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Jamestown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Jamestown, September typically has an average temperature of 19°C (66°F), with highs reaching up to 33°C (91°F) and lows dropping to around 3°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec283138486068737166554034
Data source: Temperature data for Jamestown generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Jamestown

In Jamestown in September, the precipitation amount is 100 mm (3.9 in) over a span of 10 days.

September Precipitation Trends in Jamestown

The chart displays monthly precipitation patterns in Jamestown, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Jamestown, September typically receives around 100 mm (3.9 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec96102111130140138138102100124105102
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Jamestown

In Jamestown in September, humidity is 77%. With an average temperature of 19°C (66°F), this humidity feels like a heavy blanket wrapping around you, making the air feel thick and sticky, which can be quite uncomfortable for traveling.

September Average Humidity in Jamestown

This chart illustrates the average monthly humidity levels in Jamestown, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Jamestown is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%87%81%83%82%76%77%82%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Jamestown

In Jamestown in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Jamestown.

Maximum UV Index Levels in Jamestown for September

The chart shows the monthly maximum UV Index (UVI) for Jamestown in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Jamestown typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec346910101098642
Data source: Jamestown September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Jamestown Compares to Other Months

Weather in Jamestown varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Jamestown, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Jamestown, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)96 mm (3.8 inches)88%moderate
February Weather-1°C (31°F)102 mm (4.0 inches)88%moderate
March Weather3°C (38°F)111 mm (4.4 inches)87%high
April Weather9°C (48°F)130 mm (5.1 inches)87%very high
May Weather15°C (60°F)140 mm (5.5 inches)81%very high
June Weather20°C (68°F)138 mm (5.4 inches)83%very high
July Weather23°C (73°F)138 mm (5.4 inches)82%very high
August Weather21°C (71°F)102 mm (4.0 inches)76%very high
September Weather19°C (66°F)100 mm (3.9 inches)77%very high
October Weather13°C (55°F)124 mm (4.9 inches)82%high
November Weather4°C (40°F)105 mm (4.1 inches)89%moderate
December Weather1°C (34°F)102 mm (4.0 inches)86%low

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