September Weather in Naples, United States

Last updated: June 24, 2025

In September, the average temperature in Naples, United States hovers around 18°C (64°F). This month can bring extremes, with temperatures dipping as low as 0°C (33°F) and soaring up to 35°C (95°F). Expect a modest 19 mm (0.8 in) of precipitation over just 2 days, and enjoy a comfortable average humidity of 50%.

September Temperature in Naples

In September in Naples, the average temperature is 18°C (64°F). Maximum temperatures can reach 35°C (95°F), while minimums can drop as low as 0°C (33°F). Dress in layers to enjoy the varied climate and take advantage of outdoor activities throughout the day.

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

The chart illustrates September temperature patterns in Naples, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Naples, September typically has an average temperature of 18°C (64°F), with highs reaching up to 35°C (95°F) and lows dropping to around 0°C (33°F).

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

September Precipitation in Naples

In Naples in September, the precipitation amount is 19 mm (0.8 in) over a span of 2 days.

September Precipitation Trends in Naples

The chart displays monthly precipitation patterns in Naples, 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 Naples, September typically receives around 19 mm (0.8 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 Naples

In Naples in September, humidity is 50%. With an average temperature of 18°C (64°F), this humidity feels like a refreshing embrace, making it quite pleasant for traveling as you can comfortably explore without the discomfort of excessive sweat.

September Average Humidity in Naples

This chart illustrates the average monthly humidity levels in Naples, 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 Naples is approximately 50%, 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 Naples

In Naples in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Naples.

Maximum UV Index Levels in Naples for September

The chart shows the monthly maximum UV Index (UVI) for Naples 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 Naples typically reaches 10, which falls under the very high exposure category.

Data source: Naples 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 Naples Compares to Other Months

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

This table compares monthly weather conditions in Naples, 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)	26 mm (1.0 inches)	92%	moderate
February Weather	-4°C (25°F)	38 mm (1.5 inches)	93%	high
March Weather	2°C (37°F)	40 mm (1.6 inches)	85%	very high
April Weather	8°C (46°F)	31 mm (1.2 inches)	73%	very high
May Weather	14°C (57°F)	33 mm (1.3 inches)	64%	extreme
June Weather	21°C (70°F)	17 mm (0.7 inches)	57%	extreme
July Weather	25°C (77°F)	11 mm (0.4 inches)	45%	extreme
August Weather	23°C (73°F)	18 mm (0.7 inches)	41%	extreme
September Weather	18°C (64°F)	19 mm (0.8 inches)	50%	very high
October Weather	8°C (46°F)	35 mm (1.4 inches)	70%	high
November Weather	3°C (37°F)	22 mm (0.9 inches)	84%	moderate
December Weather	-4°C (25°F)	28 mm (1.1 inches)	90%	moderate