September Weather in Fullerton

Last updated: March 2, 2024

The weather in Fullerton, United States, during September is characterized by an average temperature of 20°C (69°F). Highs can soar to 34°C (94°F), while lows may dip to 6°C (43°F). Typically, the humidity level in Fullerton throughout September hovers around 77%.

6°C (43°F)

Minimum temperature

20°C (69°F)

Average temperature

34°C (94°F)

Maximum temperature

77%

Humidity

Precipitation and Sunshine hours

In September, Fullerton averages 57 mm (2.2 inches) of rainfall, typically over the course of 7 rainy days. The month enjoys an average of 12 hours 24 minutes of daylight, with the sun shining for approximately 9 hours 35 minutes each day. Additionally, there is a 72% probability of sunny days during this period.

57 mm (2.2 inches)

Precipitation

7 rainy days

Rainy days

9 hours 35 minutes

Sunshine hours

72%

Chance of sun

UV Index

In September, the UV Index in Fullerton 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 7 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

Compare Fullerton's Climate with Cities Worldwide