September Weather in Rochester, United States

Last updated: June 24, 2025

In September, the average temperature in Rochester, United States is a comfortable 18°C (64°F). However, be prepared for a range, as temperatures can dip to a chilly 1°C (34°F) or soar up to a warm 32°C (91°F). During this month, expect about 122 mm (4.8 in) of precipitation over 9 days, with an average humidity level of 75%.

September Temperature in Rochester

In September, in Rochester, the average temperature is 18°C (64°F). Maximums can reach 32°C (91°F) and minimums can drop as low as 1°C (34°F). Travelers should be prepared for a range of temperatures, making layers a wise choice for their visit.

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

The chart illustrates September temperature patterns in Rochester, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rochester, September typically has an average temperature of 18°C (64°F), with highs reaching up to 32°C (91°F) and lows dropping to around 1°C (34°F).

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

September Precipitation in Rochester

In Rochester in September, the precipitation amount is 122 mm (4.8 in) over a span of 9 days.

September Precipitation Trends in Rochester

The chart displays monthly precipitation patterns in Rochester, 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 Rochester, September typically receives around 122 mm (4.8 inches) of precipitation spread over approximately 9 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 Rochester

In Rochester in September, humidity is 75%. With an average temperature of 18°C (64°F), this humidity feels like a warm blanket enveloping you, making your travels a bit sticky and requiring frequent breaks in the shade to stay comfortable.

September Average Humidity in Rochester

This chart illustrates the average monthly humidity levels in Rochester, 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 Rochester is approximately 75%, 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 Rochester

In Rochester 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 Rochester.

Maximum UV Index Levels in Rochester for September

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

Data source: Rochester 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 Rochester Compares to Other Months

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

This table compares monthly weather conditions in Rochester, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-8°C (17°F)	36 mm (1.4 inches)	82%	moderate
February Weather	-8°C (18°F)	47 mm (1.8 inches)	84%	moderate
March Weather	1°C (34°F)	59 mm (2.3 inches)	80%	moderate
April Weather	6°C (44°F)	88 mm (3.4 inches)	81%	very high
May Weather	15°C (59°F)	143 mm (5.6 inches)	74%	very high
June Weather	21°C (71°F)	135 mm (5.3 inches)	80%	very high
July Weather	23°C (74°F)	99 mm (3.9 inches)	80%	very high
August Weather	21°C (70°F)	118 mm (4.6 inches)	77%	very high
September Weather	18°C (64°F)	122 mm (4.8 inches)	75%	very high
October Weather	9°C (48°F)	110 mm (4.3 inches)	80%	moderate
November Weather	1°C (34°F)	47 mm (1.8 inches)	87%	moderate
December Weather	-4°C (25°F)	42 mm (1.6 inches)	83%	low