September Weather in Morristown, United States

Last updated: June 24, 2025

In Morristown, United States, the average temperature in September hovers around 18°C (65°F). Expect a minimum of 2°C (36°F) and a peak of 33°C (91°F) during this time. Precipitation is notable, with 139 mm (5.5 in) of rain spread over 10 days, contributing to an average humidity level of 81%. Enjoy the dynamic weather as it transforms the landscape!

September Temperature in Morristown

In September in Morristown, the average temperature is 18°C (65°F), with maximums reaching 33°C (91°F) and minimums dropping as low as 2°C (36°F). This makes Morristown an ideal destination for travelers seeking a mix of comfortable days and cooler evenings.

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

The chart illustrates September temperature patterns in Morristown, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Morristown, September typically has an average temperature of 18°C (65°F), with highs reaching up to 33°C (91°F) and lows dropping to around 2°C (36°F).

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

September Precipitation in Morristown

In Morristown, in September, the total precipitation amount is 139 mm (5.5 in) accumulated over 10 days.

September Precipitation Trends in Morristown

The chart displays monthly precipitation patterns in Morristown, 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 Morristown, September typically receives around 139 mm (5.5 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 Morristown

In Morristown in September, humidity is 81%. With an average temperature of 18°C (65°F), this humidity feels like a thick blanket wrapping around you, making every step feel heavier and the air thick and sultry—a challenging environment for traveling.

September Average Humidity in Morristown

This chart illustrates the average monthly humidity levels in Morristown, 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 Morristown is approximately 81%, 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 Morristown

In Morristown 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 Morristown.

Maximum UV Index Levels in Morristown for September

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

Data source: Morristown 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 Morristown Compares to Other Months

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

This table compares monthly weather conditions in Morristown, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-9°C (17°F)	35 mm (1.4 inches)	87%	moderate
February Weather	-9°C (17°F)	39 mm (1.5 inches)	90%	moderate
March Weather	1°C (33°F)	65 mm (2.6 inches)	85%	moderate
April Weather	6°C (44°F)	89 mm (3.5 inches)	84%	very high
May Weather	15°C (59°F)	136 mm (5.3 inches)	78%	very high
June Weather	22°C (72°F)	114 mm (4.5 inches)	80%	very high
July Weather	23°C (74°F)	112 mm (4.4 inches)	81%	very high
August Weather	21°C (71°F)	136 mm (5.3 inches)	81%	very high
September Weather	18°C (65°F)	139 mm (5.5 inches)	81%	very high
October Weather	9°C (49°F)	91 mm (3.6 inches)	84%	moderate
November Weather	1°C (34°F)	37 mm (1.5 inches)	88%	moderate
December Weather	-4°C (25°F)	46 mm (1.8 inches)	84%	low