September Weather in Walnut Creek

Last updated: March 2, 2024

The weather in Walnut Creek, United States, during September is characterized by an average temperature of 20°C (68°F). Highs can soar to 32°C (90°F), while lows may dip to 8°C (47°F). Typically, the humidity level in Walnut Creek throughout September hovers around 77%.

8°C (47°F)

Minimum temperature

20°C (68°F)

Average temperature

32°C (90°F)

Maximum temperature

77%

Humidity

Precipitation and Sunshine hours

In September, Walnut Creek averages 105 mm (4.2 inches) of rainfall, typically over the course of 10 rainy days. The month enjoys an average of 12 hours 24 minutes of daylight, with the sun shining for approximately 9 hours 20 minutes each day. Additionally, there is a 54% probability of sunny days during this period.

105 mm (4.2 inches)

Precipitation

10 rainy days

Rainy days

9 hours 20 minutes

Sunshine hours

54%

Chance of sun

UV Index

In September, the UV Index in Walnut Creek reaches a maximum of 8, indicating a level of VeryHigh exposure. The most intense UV radiation typically occurs between 13:00 and 15:00, during which unprotected skin may burn in as little as 15 minutes.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
  07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00
UVI 1 1 2 3 5 7 8 8 6 5 3 1 1
Exposure Low Moderate High VeryHigh High Moderate Low
Time to burn 45 min 30 min 25 min 15 min 25 min 30 min 45 min

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