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September Weather in Chico, United States

Last updated: June 24, 2025

The average temperature in Chico, United States during September is a pleasant 25°C (78°F). However, temperatures can vary, with a minimum of 9°C (49°F) and a maximum reaching 37°C (100°F). Expect about 88 mm (3.5 in) of precipitation spread over 7 days, and enjoy an average humidity of 64%, making for a refreshing month!

September Temperature in Chico

In September in Chico, the average temperature is 25°C (78°F). Maximums can reach 37°C (100°F), and minimums can be as low as 9°C (49°F). This climate makes Chico an ideal destination for travelers seeking warm weather with the option for cooler evenings.

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

The chart illustrates September temperature patterns in Chico, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Chico, September typically has an average temperature of 25°C (78°F), with highs reaching up to 37°C (100°F) and lows dropping to around 9°C (49°F).
JanFebMarAprMayJunJulAugSepOctNovDec454759647481858478665550
Data source: Temperature data for Chico 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 Chico

In Chico in September, the precipitation amount is 88 mm (3.5 in) over a span of 7 days.

September Precipitation Trends in Chico

The chart displays monthly precipitation patterns in Chico, 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 Chico, September typically receives around 88 mm (3.5 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec47727479119803978881114747
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Chico

In Chico in September, humidity is 64%. With an average temperature of 25°C (78°F), this humidity feels like a warm blanket wrapping around you, making it feel much warmer than the actual temperature, which can be a bit stifling for traveling but also adds a lush, tropical feel to the atmosphere.

September Average Humidity in Chico

This chart illustrates the average monthly humidity levels in Chico, 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 Chico is approximately 64%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec77%76%74%75%80%80%75%67%64%70%82%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Chico

In Chico in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Chico.

Maximum UV Index Levels in Chico for September

The chart shows the monthly maximum UV Index (UVI) for Chico 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 Chico typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111111110864
Data source: Chico 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 Chico Compares to Other Months

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

This table compares monthly weather conditions in Chico, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather7°C (45°F)47 mm (1.9 inches)77%moderate
February Weather8°C (47°F)72 mm (2.8 inches)76%high
March Weather15°C (59°F)74 mm (2.9 inches)74%very high
April Weather18°C (64°F)79 mm (3.1 inches)75%very high
May Weather23°C (74°F)119 mm (4.7 inches)80%extreme
June Weather27°C (81°F)80 mm (3.1 inches)80%extreme
July Weather29°C (85°F)39 mm (1.5 inches)75%extreme
August Weather29°C (84°F)78 mm (3.1 inches)67%extreme
September Weather25°C (78°F)88 mm (3.5 inches)64%very high
October Weather19°C (66°F)111 mm (4.4 inches)70%very high
November Weather13°C (55°F)47 mm (1.9 inches)82%high
December Weather10°C (50°F)47 mm (1.8 inches)85%moderate

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