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September Weather in Redwood Valley, United States

Last updated: June 24, 2025

In Redwood Valley, United States, the average temperature in September hovers around 19°C (67°F). Expect a minimum drop to 4°C (39°F) and a scorching maximum of 41°C (106°F). Precipitation is light, with an average of only 7 mm (0.3 in) over 2 days, and the air is fairly humid, boasting an average humidity of 68%.

September Temperature in Redwood Valley

In September in Redwood Valley, the average temperature is 19°C (67°F). Maximum temperatures can reach 41°C (106°F), while minimum readings can dip as low as 4°C (39°F). Be prepared for a wide range of temperatures during your travels, ensuring you pack accordingly for both warm and cooler weather.

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

The chart illustrates September temperature patterns in Redwood Valley, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Redwood Valley, September typically has an average temperature of 19°C (67°F), with highs reaching up to 41°C (106°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec454648535867727267595044
Data source: Temperature data for Redwood 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 Redwood Valley

In Redwood Valley in September, the precipitation amount is 7 mm (0.3 in) over a period of 2 days.

September Precipitation Trends in Redwood Valley

The chart displays monthly precipitation patterns in Redwood 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 Redwood Valley, September typically receives around 7 mm (0.3 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec172170136795431185492115
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Redwood Valley

In Redwood Valley in September, humidity is 68%. With an average temperature of 19°C (67°F), this humidity feels like a warm, enveloping blanket, making travel pleasant yet slightly muggy, which can be refreshing while exploring but may require occasional breaks to stay comfortable.

September Average Humidity in Redwood Valley

This chart illustrates the average monthly humidity levels in Redwood 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 Redwood Valley is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%83%80%80%76%70%66%68%72%84%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Redwood Valley

In Redwood Valley in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Redwood Valley.

Maximum UV Index Levels in Redwood Valley for September

The chart shows the monthly maximum UV Index (UVI) for Redwood 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 Redwood Valley typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3578111111109743
Data source: Redwood 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 Redwood Valley Compares to Other Months

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

This table compares monthly weather conditions in Redwood Valley, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather7°C (45°F)172 mm (6.8 inches)86%moderate
February Weather8°C (46°F)170 mm (6.7 inches)84%moderate
March Weather9°C (48°F)135 mm (5.3 inches)83%high
April Weather12°C (53°F)79 mm (3.1 inches)80%very high
May Weather15°C (58°F)54 mm (2.1 inches)80%extreme
June Weather19°C (67°F)3 mm (0.1 inches)76%extreme
July Weather22°C (72°F)1 mm (0.0 inches)70%extreme
August Weather22°C (72°F)1 mm (0.1 inches)66%very high
September Weather19°C (67°F)7 mm (0.3 inches)68%very high
October Weather15°C (59°F)54 mm (2.1 inches)72%high
November Weather10°C (50°F)92 mm (3.6 inches)84%moderate
December Weather7°C (45°F)115 mm (4.5 inches)84%moderate

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