September Weather in Prosser, United States

Last updated: June 24, 2025

In Prosser, United States, the average temperature in September hovers around 20°C (69°F), with lows dipping to 5°C (40°F) and highs soaring up to 39°C (103°F). Expect a sprinkle of rain, with a total precipitation of 9 mm (0.3 in) over just 2 days. The air brings a comfortable average humidity of 60%, making this an ideal time for outdoor adventures!

September Temperature in Prosser

In September, in Prosser, the average temperature is 20°C (69°F). Maximum temperatures can reach up to 39°C (103°F), while the minimum can drop as low as 5°C (40°F). It's advisable to pack accordingly to enjoy the diverse weather conditions during your travels.

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

The chart illustrates September temperature patterns in Prosser, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Prosser, September typically has an average temperature of 20°C (69°F), with highs reaching up to 39°C (103°F) and lows dropping to around 5°C (40°F).

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

September Precipitation in Prosser

In Prosser in September, the precipitation amount is 9 mm (0.3 in) over a period of 2 days.

September Precipitation Trends in Prosser

The chart displays monthly precipitation patterns in Prosser, 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 Prosser, September typically receives around 9 mm (0.3 inches) of precipitation spread over approximately 2 days.

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

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Millimeters (mm) Inches (in)

September Humidity in Prosser

In Prosser in September humidity is 60%. With an average temperature of 20°C (69°F), this humidity feels like a warm embrace, making it quite pleasant for traveling, as the air is soft and invigorating, perfect for exploring the sights and enjoying the local culture without feeling overwhelmed.

September Average Humidity in Prosser

This chart illustrates the average monthly humidity levels in Prosser, 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 Prosser is approximately 60%, 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 Prosser

In Prosser in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Prosser.

Maximum UV Index Levels in Prosser for September

The chart shows the monthly maximum UV Index (UVI) for Prosser 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 Prosser typically reaches 7, which falls under the high exposure category.

Data source: Prosser 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 Prosser Compares to Other Months

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

This table compares monthly weather conditions in Prosser, 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)	39 mm (1.5 inches)	85%	low
February Weather	2°C (36°F)	39 mm (1.5 inches)	86%	moderate
March Weather	8°C (46°F)	24 mm (0.9 inches)	86%	moderate
April Weather	13°C (55°F)	22 mm (0.9 inches)	82%	high
May Weather	19°C (66°F)	15 mm (0.6 inches)	77%	very high
June Weather	23°C (74°F)	6 mm (0.2 inches)	79%	very high
July Weather	27°C (81°F)	1 mm (0.0 inches)	77%	very high
August Weather	27°C (80°F)	4 mm (0.1 inches)	62%	very high
September Weather	20°C (69°F)	9 mm (0.3 inches)	60%	high
October Weather	12°C (53°F)	24 mm (1.0 inches)	80%	moderate
November Weather	5°C (42°F)	31 mm (1.2 inches)	87%	moderate
December Weather	2°C (35°F)	31 mm (1.2 inches)	86%	low