September Weather in Plain, United States

Last updated: June 24, 2025

In September, the average temperature in Plain, United States hovers around 18°C (65°F). Visitors can expect a minimum chill of 2°C (36°F), while highs can reach up to 33°C (92°F). With an average precipitation of 117 mm (4.6 in) spread over 10 days and a humidity level of 74%, it's a month that showcases the region's varied climate. Be prepared for a mix of weather conditions!

September Temperature in Plain

In September, in Plain, the average temperature is 18°C (65°F). The maximum can reach 33°C (92°F), while the minimum can be as low as 2°C (36°F). This temperature range makes Plain an ideal destination for travelers seeking both warm days and cool nights.

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

The chart illustrates September temperature patterns in Plain, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Plain, September typically has an average temperature of 18°C (65°F), with highs reaching up to 33°C (92°F) and lows dropping to around 2°C (36°F).

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

September Precipitation in Plain

In Plain in September, the total precipitation amount is 117 mm (4.6 in) recorded over a span of 10 days.

September Precipitation Trends in Plain

The chart displays monthly precipitation patterns in Plain, 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 Plain, September typically receives around 117 mm (4.6 inches) of precipitation spread over approximately 10 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 Plain

In Plain in September humidity is 74%. With an average temperature of 18°C (65°F), this humidity feels like a warm, sticky embrace that can make even short walks feel laborious, leading travelers to seek shade and refreshment more often.

September Average Humidity in Plain

This chart illustrates the average monthly humidity levels in Plain, 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 Plain is approximately 74%, 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 Plain

In Plain in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Plain.

Maximum UV Index Levels in Plain for September

The chart shows the monthly maximum UV Index (UVI) for Plain 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 Plain typically reaches 8, which falls under the very high exposure category.

Data source: Plain 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 Plain Compares to Other Months

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

This table compares monthly weather conditions in Plain, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-6°C (21°F)	45 mm (1.8 inches)	84%	low
February Weather	-6°C (22°F)	55 mm (2.2 inches)	85%	moderate
March Weather	2°C (36°F)	56 mm (2.2 inches)	84%	moderate
April Weather	8°C (46°F)	85 mm (3.4 inches)	83%	very high
May Weather	15°C (60°F)	130 mm (5.1 inches)	75%	very high
June Weather	21°C (71°F)	113 mm (4.4 inches)	79%	very high
July Weather	24°C (75°F)	95 mm (3.7 inches)	75%	very high
August Weather	22°C (71°F)	106 mm (4.2 inches)	69%	very high
September Weather	18°C (65°F)	117 mm (4.6 inches)	74%	very high
October Weather	10°C (51°F)	114 mm (4.5 inches)	79%	moderate
November Weather	2°C (36°F)	45 mm (1.8 inches)	88%	moderate
December Weather	-2°C (29°F)	43 mm (1.7 inches)	82%	low