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September Weather in Saint Peter, United States

Last updated: June 24, 2025

In September, the average temperature in Saint Peter, United States hovers around 18°C (64°F), making it a pleasant time to visit. Expect temperature extremes ranging from a cool 2°C (37°F) to a balmy 33°C (92°F). Rainfall is common, with an average precipitation of 83 mm (3.3 in) spread over about 10 days. Additionally, you can anticipate a relatively high average humidity of 79%, contributing to the season's unique atmosphere.

September Temperature in Saint Peter

In September in Saint Peter, the average temperature is 18°C (64°F). Maximums can reach 33°C (92°F), while minimums can dip as low as 2°C (37°F). Be prepared for a wide range of temperatures when traveling during this time.

September Weather in Saint Peter: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Saint Peter, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint Peter, September typically has an average temperature of 18°C (64°F), with highs reaching up to 33°C (92°F) and lows dropping to around 2°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec212234445768737064513628
Data source: Temperature data for Saint Peter 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 Saint Peter

In Saint Peter in September, the total precipitation amount is 83 mm (3.3 in) over a span of 10 days.

September Precipitation Trends in Saint Peter

The chart displays monthly precipitation patterns in Saint Peter, 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 Saint Peter, September typically receives around 83 mm (3.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec47475810311810410893831064446
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Saint Peter

In Saint Peter in September, humidity is 79%. With an average temperature of 18°C (64°F), this humidity feels like a warm, sticky embrace that can make outdoor activities more challenging but also creates a lush, vibrant atmosphere that's perfect for exploring local culture and scenery.

September Average Humidity in Saint Peter

This chart illustrates the average monthly humidity levels in Saint Peter, 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 Saint Peter is approximately 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%85%85%85%78%80%78%76%79%83%88%82%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Saint Peter

In Saint Peter in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Saint Peter.

Maximum UV Index Levels in Saint Peter for September

The chart shows the monthly maximum UV Index (UVI) for Saint Peter 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 Saint Peter typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24589101097532
Data source: Saint Peter 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 Saint Peter Compares to Other Months

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

This table compares monthly weather conditions in Saint Peter, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (21°F)47 mm (1.9 inches)85%low
February Weather-6°C (22°F)47 mm (1.9 inches)85%moderate
March Weather1°C (34°F)58 mm (2.3 inches)85%moderate
April Weather7°C (44°F)103 mm (4.1 inches)85%very high
May Weather14°C (58°F)118 mm (4.6 inches)78%very high
June Weather20°C (69°F)104 mm (4.1 inches)80%very high
July Weather23°C (74°F)108 mm (4.2 inches)78%very high
August Weather21°C (71°F)93 mm (3.7 inches)76%very high
September Weather18°C (64°F)83 mm (3.3 inches)79%high
October Weather10°C (51°F)106 mm (4.2 inches)83%moderate
November Weather2°C (36°F)44 mm (1.7 inches)88%moderate
December Weather-2°C (29°F)46 mm (1.8 inches)81%low

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