September Weather in Islesboro, United States

Last updated: June 24, 2025

In September, the average temperature in Islesboro, United States is a pleasant 16°C (61°F), with daily fluctuations ranging from a minimum of 9°C (48°F) to a maximum of 23°C (74°F). This month also brings about 99 mm (3.9 in) of precipitation over approximately 8 days, contributing to an average humidity level of 77%.

September Temperature in Islesboro

In September in Islesboro, the average temperature is 16°C (61°F). The maximum can reach 23°C (74°F), and the minimum can be as low as 9°C (48°F). This pleasant climate makes it a great time for outdoor activities and exploring local attractions.

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

The chart illustrates September temperature patterns in Islesboro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Islesboro, September typically has an average temperature of 16°C (61°F), with highs reaching up to 23°C (74°F) and lows dropping to around 9°C (48°F).

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

September Precipitation in Islesboro

In Islesboro in September, the precipitation amount is 99 mm (3.9 in) spread over 8 days.

September Precipitation Trends in Islesboro

The chart displays monthly precipitation patterns in Islesboro, 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 Islesboro, September typically receives around 99 mm (3.9 inches) of precipitation spread over approximately 8 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 Islesboro

In Islesboro in September humidity is 77%. With an average temperature of 16°C (61°F), this humidity feels like a slight heaviness in the air, making every step feel a touch more effortful while traveling. The dampness clings to your skin, adding a layer of discomfort, yet the mild temperature invites you to explore the surroundings, blending the challenge of the humidity with an opportunity for a refreshing adventure.

September Average Humidity in Islesboro

This chart illustrates the average monthly humidity levels in Islesboro, 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 Islesboro is approximately 77%, 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 Islesboro

In Islesboro in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Islesboro.

Maximum UV Index Levels in Islesboro for September

The chart shows the monthly maximum UV Index (UVI) for Islesboro 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 Islesboro typically reaches 7, which falls under the high exposure category.

Data source: Islesboro 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 Islesboro Compares to Other Months

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

This table compares monthly weather conditions in Islesboro, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (28°F)	112 mm (4.4 inches)	88%	low
February Weather	-2°C (29°F)	108 mm (4.2 inches)	88%	moderate
March Weather	0°C (33°F)	89 mm (3.5 inches)	85%	moderate
April Weather	5°C (41°F)	169 mm (6.7 inches)	81%	high
May Weather	9°C (49°F)	114 mm (4.5 inches)	76%	very high
June Weather	14°C (58°F)	87 mm (3.4 inches)	74%	very high
July Weather	17°C (63°F)	100 mm (3.9 inches)	74%	very high
August Weather	18°C (65°F)	90 mm (3.5 inches)	74%	very high
September Weather	16°C (61°F)	99 mm (3.9 inches)	77%	high
October Weather	12°C (54°F)	169 mm (6.6 inches)	82%	moderate
November Weather	6°C (42°F)	145 mm (5.7 inches)	85%	moderate
December Weather	0°C (33°F)	160 mm (6.3 inches)	84%	low