September Weather in Richland, United States

Last updated: June 24, 2025

In Richland, United States, the average temperature in September is a pleasant 22°C (73°F). However, expect a range, with minimums dipping to 7°C (45°F) and maximums soaring to 35°C (95°F). This month also sees around 51 mm (2.0 in) of precipitation over 7 days, contributing to an average humidity of 64%. Stay prepared for a mix of sunshine and occasional showers!

September Temperature in Richland

In September in Richland, the average temperature is 22°C (73°F). Maximums can reach 35°C (95°F) and minimums can be as low as 7°C (45°F). Be prepared for a warm climate with the possibility of cooler evenings, making it an ideal time to explore outdoor activities.

September Weather in Richland: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Richland, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Richland, September typically has an average temperature of 22°C (73°F), with highs reaching up to 35°C (95°F) and lows dropping to around 7°C (45°F).

Data source: Temperature data for Richland generated using information from the Copernicus Climate Change Service.

September Precipitation in Richland

In Richland in September, the precipitation amount is 51 mm (2.0 in) over a period of 7 days.

September Precipitation Trends in Richland

The chart displays monthly precipitation patterns in Richland, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Richland, September typically receives around 51 mm (2.0 inches) of precipitation spread over approximately 7 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Richland

In Richland in September humidity is 64%. With an average temperature of 22°C (73°F), this humidity feels like a warm embrace, making traveling comfortable yet slightly sticky, as you enjoy the vibrant sights while needing to stay hydrated.

September Average Humidity in Richland

This chart illustrates the average monthly humidity levels in Richland, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Richland is approximately 64%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Richland

In Richland in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Richland.

Maximum UV Index Levels in Richland for September

The chart shows the monthly maximum UV Index (UVI) for Richland in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Richland typically reaches 9, which falls under the very high exposure category.

Data source: Richland September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Richland Compares to Other Months

Weather in Richland varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Richland, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Richland, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (34°F)	79 mm (3.1 inches)	81%	moderate
February Weather	3°C (37°F)	80 mm (3.2 inches)	78%	high
March Weather	9°C (49°F)	130 mm (5.1 inches)	76%	high
April Weather	13°C (55°F)	148 mm (5.8 inches)	78%	very high
May Weather	19°C (66°F)	165 mm (6.5 inches)	83%	very high
June Weather	24°C (76°F)	95 mm (3.7 inches)	83%	extreme
July Weather	26°C (79°F)	98 mm (3.9 inches)	78%	extreme
August Weather	25°C (76°F)	91 mm (3.6 inches)	68%	very high
September Weather	22°C (73°F)	51 mm (2.0 inches)	64%	very high
October Weather	15°C (59°F)	134 mm (5.3 inches)	70%	high
November Weather	8°C (46°F)	64 mm (2.5 inches)	83%	moderate
December Weather	5°C (41°F)	52 mm (2.1 inches)	87%	moderate