September Weather in San Bernardino

Last updated: March 2, 2024

The weather in San Bernardino, United States, during September is characterized by an average temperature of 23°C (74°F). Highs can soar to 39°C (102°F), while lows may dip to 13°C (55°F). Typically, the humidity level in San Bernardino throughout September hovers around 52%.

13°C (55°F)

Minimum temperature

23°C (74°F)

Average temperature

39°C (102°F)

Maximum temperature

52%

Humidity

Precipitation and Sunshine hours

In September, San Bernardino averages 10 mm (0.4 inches) of rainfall, typically over the course of 1 rainy days. The month enjoys an average of 12 hours 20 minutes of daylight, with the sun shining for approximately 10 hours 42 minutes each day. Additionally, there is a 85% probability of sunny days during this period.

10 mm (0.4 inches)

Precipitation

1 rainy days

Rainy days

10 hours 42 minutes

Sunshine hours

85%

Chance of sun

UV Index

In September, the UV Index in San Bernardino reaches a maximum of 10, indicating a level of VeryHigh exposure. The most intense UV radiation typically occurs between 12:00 and 14:00, 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 2 3 6 8 10 10 9 7 4 2 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

Compare San Bernardino's Climate with Cities Worldwide