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September Weather in Gridley, United States

Last updated: June 24, 2025

In Gridley, United States, the weather in September is pleasantly mild, with an average temperature of 21°C (70°F). Expect a minimum of 5°C (41°F) and a maximum of 35°C (95°F), offering a wide range for outdoor activities. Prepare for some rain, as the area typically sees 67 mm (2.7 in) of precipitation spread over 8 days. With an average humidity of 80%, the air tends to feel quite refreshing during this time.

September Temperature in Gridley

In September in Gridley, the average temperature is 21°C (70°F). Maximums can reach 35°C (95°F), while minimums can drop to 5°C (41°F). This variability in temperature makes it essential for travelers to pack both lightweight clothing for the warm days and warmer layers for the cooler evenings.

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

The chart illustrates September temperature patterns in Gridley, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Gridley, September typically has an average temperature of 21°C (70°F), with highs reaching up to 35°C (95°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec272941516474777469564034
Data source: Temperature data for Gridley 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 Gridley

In Gridley in September, the precipitation amount is 67 mm (2.7 in) during a total of 8 days.

September Precipitation Trends in Gridley

The chart displays monthly precipitation patterns in Gridley, 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 Gridley, September typically receives around 67 mm (2.7 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec616810511616112610687671275755
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Gridley

In Gridley in September humidity is 80%. With an average temperature of 21°C (70°F), this humidity feels like a warm, enveloping blanket that can make even short walks feel draining, urging travelers to seek shade or a cool drink frequently.

September Average Humidity in Gridley

This chart illustrates the average monthly humidity levels in Gridley, 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 Gridley is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%83%84%85%79%82%80%81%80%82%88%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Gridley

In Gridley 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 Gridley.

Maximum UV Index Levels in Gridley for September

The chart shows the monthly maximum UV Index (UVI) for Gridley 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 Gridley typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357810111098642
Data source: Gridley 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 Gridley Compares to Other Months

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

This table compares monthly weather conditions in Gridley, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)61 mm (2.4 inches)82%moderate
February Weather-2°C (29°F)68 mm (2.7 inches)83%moderate
March Weather5°C (42°F)105 mm (4.1 inches)84%high
April Weather10°C (51°F)116 mm (4.6 inches)85%very high
May Weather18°C (64°F)161 mm (6.3 inches)79%very high
June Weather23°C (74°F)126 mm (5.0 inches)82%extreme
July Weather25°C (77°F)106 mm (4.2 inches)80%very high
August Weather23°C (74°F)87 mm (3.4 inches)81%very high
September Weather21°C (70°F)67 mm (2.7 inches)80%very high
October Weather13°C (56°F)127 mm (5.0 inches)82%high
November Weather5°C (40°F)57 mm (2.2 inches)88%moderate
December Weather1°C (34°F)55 mm (2.1 inches)84%low

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