September Weather in Cromwell, United States

Last updated: June 24, 2025

In September, the average temperature in Cromwell, United States hovers around 20°C (67°F), making it a pleasant time to visit. However, be prepared for temperature fluctuations, with a minimum of 4°C (40°F) and a maximum of 34°C (93°F). Expect some rainfall, as 99 mm (3.9 in) of precipitation typically falls over 9 days. Additionally, the average humidity level sits at a comfortable 68%, ensuring a refreshing atmosphere throughout the month.

September Temperature in Cromwell

In September in Cromwell, the average temperature is 20°C (67°F), with maximums reaching 34°C (93°F) and minimums dropping as low as 4°C (40°F). This range makes Cromwell an ideal destination for travelers seeking pleasant weather and the versatility to enjoy both warm days and cooler evenings.

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

The chart illustrates September temperature patterns in Cromwell, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Cromwell, September typically has an average temperature of 20°C (67°F), with highs reaching up to 34°C (93°F) and lows dropping to around 4°C (40°F).

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

September Precipitation in Cromwell

In Cromwell in September, the precipitation amount is 99 mm (3.9 in) during a span of 9 days.

September Precipitation Trends in Cromwell

The chart displays monthly precipitation patterns in Cromwell, 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 Cromwell, September typically receives around 99 mm (3.9 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 Cromwell

In Cromwell in September humidity is 68%. With an average temperature of 20°C (67°F), this humidity feels like walking through a warm, heavy blanket, making travel a bit sweltering and causing you to crave frequent breaks in the shade.

September Average Humidity in Cromwell

This chart illustrates the average monthly humidity levels in Cromwell, 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 Cromwell is approximately 68%, 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 Cromwell

In Cromwell 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 Cromwell.

Maximum UV Index Levels in Cromwell for September

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

Data source: Cromwell 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 Cromwell Compares to Other Months

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

This table compares monthly weather conditions in Cromwell, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	0°C (32°F)	67 mm (2.6 inches)	84%	moderate
February Weather	1°C (34°F)	89 mm (3.5 inches)	82%	moderate
March Weather	4°C (40°F)	90 mm (3.6 inches)	81%	high
April Weather	10°C (49°F)	126 mm (5.0 inches)	78%	very high
May Weather	15°C (60°F)	111 mm (4.4 inches)	69%	very high
June Weather	20°C (69°F)	94 mm (3.7 inches)	69%	very high
July Weather	24°C (75°F)	156 mm (6.1 inches)	62%	very high
August Weather	23°C (74°F)	96 mm (3.8 inches)	65%	very high
September Weather	20°C (67°F)	99 mm (3.9 inches)	68%	very high
October Weather	14°C (58°F)	130 mm (5.1 inches)	74%	high
November Weather	7°C (44°F)	90 mm (3.6 inches)	82%	moderate
December Weather	2°C (36°F)	127 mm (5.0 inches)	80%	low