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September Weather in Jefferson, United States

Last updated: June 24, 2025

In September, the average temperature in Jefferson, United States hovers around 21°C (71°F). Expect a varied climate where the mercury can dip to a cool 4°C (40°F) or soar up to a sweltering 35°C (95°F). Alongside this balmy weather, you'll see 105 mm (4.1 in) of precipitation over approximately 10 days, contributing to an average humidity of 68%. Prepare for a delightful mix of sun and occasional showers!

September Temperature in Jefferson

In September in Jefferson, the average temperature is 21°C (71°F). Maximums can reach 35°C (95°F) and minimums can be as low as 4°C (40°F). Be prepared for a wide range of temperatures, making it ideal for layered clothing to enjoy your travel.

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

The chart illustrates September temperature patterns in Jefferson, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Jefferson, September typically has an average temperature of 21°C (71°F), with highs reaching up to 35°C (95°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec363945556573797670614639
Data source: Temperature data for Jefferson 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 Jefferson

In Jefferson in September, the precipitation amount is 105 mm (4.1 in) over the course of 10 days.

September Precipitation Trends in Jefferson

The chart displays monthly precipitation patterns in Jefferson, 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 Jefferson, September typically receives around 105 mm (4.1 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec599588981381191381221051018894
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Jefferson

In Jefferson in September, humidity is 68%. With an average temperature of 21°C (71°F), this humidity feels like a warm embrace, making traveling a bit sticky but also inviting for leisurely strolls and outdoor adventures.

September Average Humidity in Jefferson

This chart illustrates the average monthly humidity levels in Jefferson, 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 Jefferson is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%84%78%79%70%59%68%80%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Jefferson

In Jefferson 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 Jefferson.

Maximum UV Index Levels in Jefferson for September

The chart shows the monthly maximum UV Index (UVI) for Jefferson 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 Jefferson typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098753
Data source: Jefferson 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 Jefferson Compares to Other Months

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

This table compares monthly weather conditions in Jefferson, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (36°F)59 mm (2.3 inches)86%moderate
February Weather4°C (40°F)95 mm (3.7 inches)86%moderate
March Weather7°C (45°F)87 mm (3.4 inches)86%high
April Weather13°C (55°F)98 mm (3.9 inches)84%very high
May Weather18°C (65°F)138 mm (5.4 inches)78%very high
June Weather23°C (74°F)119 mm (4.7 inches)79%very high
July Weather26°C (79°F)138 mm (5.4 inches)70%very high
August Weather25°C (77°F)122 mm (4.8 inches)59%very high
September Weather21°C (71°F)105 mm (4.1 inches)68%very high
October Weather16°C (61°F)101 mm (4.0 inches)80%high
November Weather8°C (46°F)88 mm (3.4 inches)86%moderate
December Weather4°C (39°F)94 mm (3.7 inches)85%moderate

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