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September Weather in Petersburg, United States

Last updated: June 24, 2025

In Petersburg, United States, the average temperature in September hovers around 19°C (67°F), with highs reaching up to 32°C (90°F) and lows dipping to a chilly 1°C (35°F). Expect around 108 mm (4.2 in) of precipitation spread across 9 days, along with an average humidity level of 68%.

September Temperature in Petersburg

In September in Petersburg, the average temperature is 19°C (67°F). Maximum temperatures can reach 32°C (90°F), while minimums can drop to as low as 1°C (35°F). It’s advisable to pack layers to stay comfortable while exploring the diverse climate.

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

The chart illustrates September temperature patterns in Petersburg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Petersburg, September typically has an average temperature of 19°C (67°F), with highs reaching up to 32°C (90°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec323742526269747266574237
Data source: Temperature data for Petersburg 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 Petersburg

In Petersburg in September, the precipitation amount is 108 mm (4.2 in) spread over 9 days.

September Precipitation Trends in Petersburg

The chart displays monthly precipitation patterns in Petersburg, 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 Petersburg, September typically receives around 108 mm (4.2 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec62947710312410189951081066487
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Petersburg

In Petersburg in September, humidity is 68%. With an average temperature of 19°C (67°F), this humidity feels like a warm, enveloping blanket, making travel pleasant yet slightly muggy, which can be refreshing while exploring but may require occasional breaks to stay comfortable.

September Average Humidity in Petersburg

This chart illustrates the average monthly humidity levels in Petersburg, 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 Petersburg 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 Petersburg

In Petersburg 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 Petersburg.

Maximum UV Index Levels in Petersburg for September

The chart shows the monthly maximum UV Index (UVI) for Petersburg 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 Petersburg typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35710101010108753
Data source: Petersburg 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 Petersburg Compares to Other Months

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

This table compares monthly weather conditions in Petersburg, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)62 mm (2.4 inches)86%moderate
February Weather3°C (38°F)94 mm (3.7 inches)86%moderate
March Weather6°C (43°F)77 mm (3.0 inches)86%high
April Weather11°C (52°F)103 mm (4.0 inches)84%very high
May Weather16°C (62°F)124 mm (4.9 inches)78%very high
June Weather21°C (69°F)100 mm (4.0 inches)79%very high
July Weather24°C (75°F)89 mm (3.5 inches)70%very high
August Weather22°C (72°F)95 mm (3.8 inches)59%very high
September Weather19°C (67°F)108 mm (4.2 inches)68%very high
October Weather14°C (57°F)106 mm (4.2 inches)80%high
November Weather6°C (42°F)64 mm (2.5 inches)86%moderate
December Weather3°C (37°F)87 mm (3.4 inches)85%moderate

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