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September Weather in Onawa, United States

Last updated: June 24, 2025

In Onawa, United States, the average temperature in September hovers around 20°C (69°F), with a range that can dip to a brisk 4°C (39°F) and soar up to a warm 36°C (97°F). Expect 91 mm (3.6 in) of precipitation spread over about 8 days, while the average humidity sits at a comfortable 75%.

September Temperature in Onawa

In September in Onawa, the average temperature is 20°C (69°F), with maximums reaching 36°C (97°F) and minimums dropping as low as 4°C (39°F). Be prepared for a wide temperature range and pack accordingly for your travels!

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

The chart illustrates September temperature patterns in Onawa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Onawa, September typically has an average temperature of 20°C (69°F), with highs reaching up to 36°C (97°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec242439496275777368523830
Data source: Temperature data for Onawa 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 Onawa

In Onawa in September, the total precipitation amount is 91 mm (3.6 in) over the course of 8 days.

September Precipitation Trends in Onawa

The chart displays monthly precipitation patterns in Onawa, 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 Onawa, September typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec273383711421146411091942940
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Onawa

In Onawa in September, humidity is 75%. With an average temperature of 20°C (69°F), this humidity feels like a warm, enveloping blanket, making travel a bit muggy and requiring frequent hydration breaks to stay comfortable while exploring.

September Average Humidity in Onawa

This chart illustrates the average monthly humidity levels in Onawa, 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 Onawa is approximately 75%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%80%73%75%78%82%83%81%75%75%82%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Onawa

In Onawa 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 Onawa.

Maximum UV Index Levels in Onawa for September

The chart shows the monthly maximum UV Index (UVI) for Onawa 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 Onawa typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34589111098642
Data source: Onawa 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 Onawa Compares to Other Months

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

This table compares monthly weather conditions in Onawa, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-5°C (24°F)27 mm (1.1 inches)76%moderate
February Weather-5°C (24°F)33 mm (1.3 inches)80%moderate
March Weather4°C (40°F)83 mm (3.3 inches)73%moderate
April Weather9°C (49°F)71 mm (2.8 inches)74%very high
May Weather16°C (62°F)142 mm (5.6 inches)78%very high
June Weather24°C (75°F)114 mm (4.5 inches)82%extreme
July Weather25°C (77°F)64 mm (2.5 inches)83%very high
August Weather23°C (74°F)110 mm (4.3 inches)80%very high
September Weather20°C (69°F)91 mm (3.6 inches)75%very high
October Weather11°C (52°F)94 mm (3.7 inches)75%high
November Weather4°C (39°F)29 mm (1.1 inches)82%moderate
December Weather-1°C (30°F)40 mm (1.6 inches)83%low

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