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September Weather in Rock Island, United States

Last updated: June 24, 2025

In September, the average temperature in Rock Island, United States hovers around 15°C (60°F), with a potential minimum of 1°C (35°F) and a sweltering maximum of 35°C (95°F). Expect approximately 26 mm (1.0 in) of precipitation spread over 4 days, and enjoy an average humidity of 62%. Make sure to prepare for a mix of conditions!

September Temperature in Rock Island

In September in Rock Island, the average temperature is 15°C (60°F). Maximums can reach 35°C (95°F) and minimums can be as low as 1°C (35°F). Be prepared for a wide range of temperatures during your travels, so pack accordingly!

September Weather in Rock Island: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Rock Island, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rock Island, September typically has an average temperature of 15°C (60°F), with highs reaching up to 35°C (95°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec282937465663706960463629
Data source: Temperature data for Rock Island 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 Rock Island

In Rock Island in September, the precipitation amount is 26 mm (1.0 in) over the course of 4 days.

September Precipitation Trends in Rock Island

The chart displays monthly precipitation patterns in Rock Island, 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 Rock Island, September typically receives around 26 mm (1.0 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec8476464127143526566479
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Rock Island

In Rock Island in September, humidity is 62%. With an average temperature of 15°C (60°F), this humidity feels like a warm embrace, making it a bit muggy for traveling, yet pleasantly refreshing for leisurely strolls and outdoor exploration.

September Average Humidity in Rock Island

This chart illustrates the average monthly humidity levels in Rock Island, 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 Rock Island is approximately 62%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%87%84%81%82%79%63%62%83%89%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Rock Island

In Rock Island 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 Rock Island.

Maximum UV Index Levels in Rock Island for September

The chart shows the monthly maximum UV Index (UVI) for Rock Island 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 Rock Island typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2467891097532
Data source: Rock Island 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 Rock Island Compares to Other Months

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

This table compares monthly weather conditions in Rock Island, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (28°F)84 mm (3.3 inches)86%low
February Weather-2°C (29°F)76 mm (3.0 inches)86%moderate
March Weather3°C (38°F)46 mm (1.8 inches)87%high
April Weather8°C (46°F)41 mm (1.6 inches)84%high
May Weather13°C (56°F)26 mm (1.0 inches)81%very high
June Weather17°C (63°F)14 mm (0.5 inches)82%very high
July Weather21°C (70°F)3 mm (0.1 inches)79%very high
August Weather21°C (70°F)5 mm (0.2 inches)63%very high
September Weather15°C (60°F)26 mm (1.0 inches)62%high
October Weather8°C (46°F)56 mm (2.2 inches)83%moderate
November Weather2°C (37°F)64 mm (2.5 inches)89%moderate
December Weather-1°C (30°F)79 mm (3.1 inches)88%low

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