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September Weather in Frontenac, United States

Last updated: June 24, 2025

In September, the average temperature in Frontenac, United States hovers around 23°C (74°F). Expect minimums dipping to 7°C (45°F) and maximums soaring to 35°C (95°F). Rain is a possibility, with 90 mm (3.5 in) of precipitation spread over 6 days. The atmosphere is comfortably humid, boasting an average humidity of 64%.

September Temperature in Frontenac

In September in Frontenac, the average temperature is 23°C (74°F). The maximum can reach 35°C (95°F), and the minimum can be as low as 7°C (45°F). This diverse temperature range makes Frontenac an ideal destination for travelers seeking to enjoy both warm days and cool evenings.

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

The chart illustrates September temperature patterns in Frontenac, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Frontenac, September typically has an average temperature of 23°C (74°F), with highs reaching up to 35°C (95°F) and lows dropping to around 7°C (45°F).
JanFebMarAprMayJunJulAugSepOctNovDec353750576878817874604741
Data source: Temperature data for Frontenac 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 Frontenac

In Frontenac in September, the total precipitation amount reaches 90 mm (3.5 in) over the course of 6 days.

September Precipitation Trends in Frontenac

The chart displays monthly precipitation patterns in Frontenac, 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 Frontenac, September typically receives around 90 mm (3.5 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec6662126129199100103121901195138
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Frontenac

In Frontenac in September, humidity is 64%. With an average temperature of 23°C (74°F), this humidity feels like a warm blanket wrapping around you, making outdoor exploration enjoyable yet slightly sticky, so it's best to stay hydrated and take breaks in the shade while traveling.

September Average Humidity in Frontenac

This chart illustrates the average monthly humidity levels in Frontenac, 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 Frontenac is approximately 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec81%78%76%78%83%83%78%68%64%70%83%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Frontenac

In Frontenac in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Frontenac.

Maximum UV Index Levels in Frontenac for September

The chart shows the monthly maximum UV Index (UVI) for Frontenac 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 Frontenac typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec35710101111109753
Data source: Frontenac 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 Frontenac Compares to Other Months

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

This table compares monthly weather conditions in Frontenac, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (36°F)66 mm (2.6 inches)81%moderate
February Weather3°C (38°F)62 mm (2.4 inches)78%moderate
March Weather10°C (50°F)126 mm (5.0 inches)76%high
April Weather14°C (57°F)129 mm (5.1 inches)78%very high
May Weather20°C (68°F)199 mm (7.8 inches)83%very high
June Weather25°C (78°F)100 mm (4.0 inches)83%extreme
July Weather27°C (81°F)103 mm (4.0 inches)78%extreme
August Weather26°C (79°F)121 mm (4.8 inches)68%very high
September Weather23°C (74°F)90 mm (3.5 inches)64%very high
October Weather15°C (60°F)119 mm (4.7 inches)70%high
November Weather8°C (47°F)51 mm (2.0 inches)83%moderate
December Weather5°C (42°F)38 mm (1.5 inches)87%moderate

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