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September Weather in Pierre, United States

Last updated: June 24, 2025

In September, the average temperature in Pierre, United States is a pleasant 19°C (66°F). However, be prepared for a temperature range that can dip to a chilly 3°C (38°F) or soar to a hot 36°C (97°F). With an average precipitation amount of 60 mm (2.3 in) over approximately 6 days, you might encounter a few showers. The overall average humidity sits at a comfortable 73%, making this month a balanced experience in terms of weather!

September Temperature in Pierre

In September in Pierre, the average temperature is 19°C (66°F). The maximum can reach 36°C (97°F), and the minimum can be as low as 3°C (38°F). It's a great time to visit if you enjoy mild weather with the possibility of hot days and cooler nights.

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

The chart illustrates September temperature patterns in Pierre, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Pierre, September typically has an average temperature of 19°C (66°F), with highs reaching up to 36°C (97°F) and lows dropping to around 3°C (38°F).
JanFebMarAprMayJunJulAugSepOctNovDec201934445973787466473627
Data source: Temperature data for Pierre 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 Pierre

In Pierre, in September, the precipitation amount is 60 mm (2.3 in) over a span of 6 days.

September Precipitation Trends in Pierre

The chart displays monthly precipitation patterns in Pierre, 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 Pierre, September typically receives around 60 mm (2.3 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec151938497862865360541126
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Pierre

In Pierre in September humidity is 73%. With an average temperature of 19°C (66°F), this humidity feels like a warm embrace, making travel enjoyable yet slightly sticky, as you find yourself seeking shade and refreshing drinks while exploring.

September Average Humidity in Pierre

This chart illustrates the average monthly humidity levels in Pierre, 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 Pierre is approximately 73%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%81%72%73%75%82%83%82%73%71%78%76%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Pierre

In Pierre 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 Pierre.

Maximum UV Index Levels in Pierre for September

The chart shows the monthly maximum UV Index (UVI) for Pierre 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 Pierre typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec25579101098532
Data source: Pierre 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 Pierre Compares to Other Months

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

This table compares monthly weather conditions in Pierre, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-7°C (20°F)15 mm (0.6 inches)78%low
February Weather-7°C (19°F)19 mm (0.8 inches)81%moderate
March Weather1°C (34°F)38 mm (1.5 inches)71%moderate
April Weather7°C (44°F)49 mm (1.9 inches)73%high
May Weather15°C (59°F)78 mm (3.1 inches)75%very high
June Weather23°C (73°F)62 mm (2.4 inches)82%very high
July Weather25°C (78°F)86 mm (3.4 inches)83%very high
August Weather23°C (74°F)53 mm (2.1 inches)82%very high
September Weather19°C (66°F)60 mm (2.3 inches)73%very high
October Weather9°C (48°F)54 mm (2.1 inches)71%moderate
November Weather2°C (36°F)11 mm (0.4 inches)78%moderate
December Weather-3°C (27°F)26 mm (1.0 inches)76%low

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