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September Weather in Central Valley, United States

Last updated: June 24, 2025

In Central Valley, United States, the average temperature in September hovers around 16°C (61°F), making it a mild time of year. Expect temperature fluctuations, with minimums dipping to -8°C (19°F) and maximums soaring to 33°C (92°F). Precipitation is relatively low, totaling just 23 mm (0.9 in) over the course of 4 days, while average humidity rests at a comfortable 47%.

September Temperature in Central Valley

In September in Central Valley, the average temperature is 16°C (61°F). Maximum temperatures can reach 33°C (92°F), while minimums can drop as low as -8°C (19°F). Therefore, be prepared for a wide range of temperatures when traveling during this time.

September Weather in Central Valley: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Central Valley, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Central Valley, September typically has an average temperature of 16°C (61°F), with highs reaching up to 33°C (92°F) and lows dropping to around -8°C (19°F).
JanFebMarAprMayJunJulAugSepOctNovDec232533415266727061443625
Data source: Temperature data for Central Valley 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 Central Valley

In Central Valley in September, the total precipitation amount is 23 mm (0.9 in) over a span of 4 days.

September Precipitation Trends in Central Valley

The chart displays monthly precipitation patterns in Central Valley, 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 Central Valley, September typically receives around 23 mm (0.9 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec42555946449212023362740
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Central Valley

In Central Valley in September, humidity is 47%. With an average temperature of 16°C (61°F), this humidity feels like a refreshing breeze that adds a touch of crispness to your travels, making it comfortable for exploring outdoor attractions without too much heaviness in the air.

September Average Humidity in Central Valley

This chart illustrates the average monthly humidity levels in Central Valley, 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 Central Valley is approximately 47%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%77%70%54%45%37%34%47%67%82%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Central Valley

In Central Valley 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 Central Valley.

Maximum UV Index Levels in Central Valley for September

The chart shows the monthly maximum UV Index (UVI) for Central Valley 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 Central Valley typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec479111112121110764
Data source: Central Valley 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 Central Valley Compares to Other Months

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

This table compares monthly weather conditions in Central Valley, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-5°C (23°F)42 mm (1.6 inches)87%moderate
February Weather-4°C (26°F)55 mm (2.2 inches)88%high
March Weather0°C (33°F)59 mm (2.3 inches)77%very high
April Weather5°C (42°F)46 mm (1.8 inches)69%extreme
May Weather11°C (52°F)44 mm (1.7 inches)54%extreme
June Weather19°C (66°F)8 mm (0.3 inches)45%extreme
July Weather22°C (72°F)21 mm (0.8 inches)37%extreme
August Weather21°C (71°F)20 mm (0.8 inches)34%extreme
September Weather16°C (61°F)23 mm (0.9 inches)47%very high
October Weather7°C (44°F)36 mm (1.4 inches)67%high
November Weather2°C (37°F)27 mm (1.1 inches)82%high
December Weather-4°C (25°F)40 mm (1.6 inches)87%moderate

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