September Weather in Palo Alto

Last updated: March 2, 2024

The weather in Palo Alto, United States, during September is characterized by an average temperature of 18°C (66°F). Highs can soar to 34°C (93°F), while lows may dip to 11°C (52°F). Typically, the humidity level in Palo Alto throughout September hovers around 55%.

11°C (52°F)

Minimum temperature

18°C (66°F)

Average temperature

34°C (93°F)

Maximum temperature

55%

Humidity

Precipitation and Sunshine hours

In September, Palo Alto averages 2 mm (0.1 inches) of rainfall, typically over the course of 0 rainy days. The month enjoys an average of 12 hours 22 minutes of daylight, with the sun shining for approximately 9 hours 57 minutes each day. Additionally, there is a 58% probability of sunny days during this period.

2 mm (0.1 inches)

Precipitation

0 rainy days

Rainy days

9 hours 57 minutes

Sunshine hours

58%

Chance of sun

UV Index

In September, the UV Index in Palo Alto reaches a maximum of 9, 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 4 6 8 9 8 6 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 Palo Alto's Climate with Cities Worldwide