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September Weather in Petersburg, United States

Last updated: June 24, 2025

In September, the average temperature in Petersburg, United States is a pleasant 22°C (71°F). However, be prepared for a range of conditions, as temperatures can drop to a minimum of 5°C (42°F) and rise as high as 35°C (95°F). You can expect about 66 mm (2.6 in) of precipitation spread over 6 days, contributing to an average humidity of 79%.

September Temperature in Petersburg

In September in Petersburg, the average temperature is 22°C (71°F). Maximums can reach up to 35°C (95°F), while minimums can drop as low as 5°C (42°F). This comfortable climate makes it an ideal time for travelers to explore and enjoy outdoor activities.

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 22°C (71°F), with highs reaching up to 35°C (95°F) and lows dropping to around 5°C (42°F).
JanFebMarAprMayJunJulAugSepOctNovDec283143526575777471574236
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 66 mm (2.6 in) over the course of 6 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 66 mm (2.6 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec676713212714613011786661086752
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 79%. With an average temperature of 22°C (71°F), this humidity feels like a warm, sticky embrace that can make any outdoor adventure quite challenging for traveling; it's advisable to stay hydrated and take breaks in the shade to fully enjoy the sights.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%84%83%80%83%82%83%79%79%88%87%
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.
JanFebMarAprMayJunJulAugSepOctNovDec357910111198643
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 Weather-2°C (29°F)67 mm (2.6 inches)84%moderate
February Weather0°C (32°F)67 mm (2.6 inches)82%moderate
March Weather6°C (44°F)132 mm (5.2 inches)84%high
April Weather11°C (53°F)127 mm (5.0 inches)83%very high
May Weather18°C (66°F)146 mm (5.7 inches)80%very high
June Weather24°C (75°F)130 mm (5.1 inches)83%extreme
July Weather25°C (78°F)117 mm (4.6 inches)82%extreme
August Weather24°C (75°F)86 mm (3.4 inches)82%very high
September Weather22°C (71°F)66 mm (2.6 inches)79%very high
October Weather14°C (57°F)108 mm (4.3 inches)79%high
November Weather5°C (42°F)67 mm (2.6 inches)88%moderate
December Weather2°C (36°F)52 mm (2.0 inches)87%moderate

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