September Weather in Rapid City

Last updated: March 2, 2024

The weather in Rapid City, United States, during September is characterized by an average temperature of 16°C (62°F). Highs can soar to 33°C (92°F), while lows may dip to 2°C (35°F). Typically, the humidity level in Rapid City throughout September hovers around 76%.

2°C (35°F)

Minimum temperature

16°C (62°F)

Average temperature

33°C (92°F)

Maximum temperature

76%

Humidity

Precipitation and Sunshine hours

In September, Rapid City averages 43 mm (1.7 inches) of rainfall, typically over the course of 7 rainy days. The month enjoys an average of 12 hours 26 minutes of daylight, with the sun shining for approximately 9 hours 35 minutes each day. Additionally, there is a 67% probability of sunny days during this period.

43 mm (1.7 inches)

Precipitation

7 rainy days

Rainy days

9 hours 35 minutes

Sunshine hours

67%

Chance of sun

UV Index

In September, the UV Index in Rapid City reaches a maximum of 8, 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 1 3 5 6 8 8 7 5 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 Rapid City's Climate with Cities Worldwide