September Weather in Maine, United States

Last updated: June 24, 2025

In September, the average temperature in Maine, United States hovers around 16°C (61°F). Expect a wide temperature range, with minimums dipping to 0°C (32°F) and maximums soaring to 32°C (90°F). Throughout the month, precipitation totals about 83 mm (3.3 in), typically falling over 10 days. The air is quite humid, with an average humidity level of 78%.

September Temperature in Maine

In September in Maine, the average temperature is 16°C (61°F). The maximum can reach 32°C (90°F) and the minimum can be as low as 0°C (32°F). Be prepared for a diverse range of weather conditions while traveling, as it can vary significantly from warm days to chilly nights.

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

The chart illustrates September temperature patterns in Maine, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Maine, September typically has an average temperature of 16°C (61°F), with highs reaching up to 32°C (90°F) and lows dropping to around 0°C (32°F).
JanFebMarAprMayJunJulAugSepOctNovDec171731415667716761473223
Data source: Temperature data for Maine generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Maine

In Maine in September, the total precipitation amount is 83 mm (3.3 in) over a span of 10 days.

September Precipitation Trends in Maine

The chart displays monthly precipitation patterns in Maine, 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 Maine, September typically receives around 83 mm (3.3 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec34505399103102118121831095052
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Maine

In Maine in September, humidity is 78%. With an average temperature of 16°C (61°F), this humidity feels like a warm, sticky embrace, making travel somewhat uncomfortable as it clings to your skin and creates a heavy atmosphere that can drain your energy.

September Average Humidity in Maine

This chart illustrates the average monthly humidity levels in Maine, 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 Maine is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%90%87%84%77%75%75%73%78%84%89%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Maine

In Maine 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 Maine.

Maximum UV Index Levels in Maine for September

The chart shows the monthly maximum UV Index (UVI) for Maine 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 Maine typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2457810997532
Data source: Maine 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 Maine Compares to Other Months

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

This table compares monthly weather conditions in Maine, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-9°C (17°F)34 mm (1.3 inches)89%low
February Weather-8°C (17°F)50 mm (2.0 inches)90%moderate
March Weather-1°C (31°F)53 mm (2.1 inches)87%moderate
April Weather5°C (42°F)98 mm (3.9 inches)84%high
May Weather13°C (56°F)103 mm (4.1 inches)77%very high
June Weather19°C (67°F)102 mm (4.0 inches)75%very high
July Weather22°C (71°F)117 mm (4.6 inches)74%very high
August Weather19°C (67°F)121 mm (4.8 inches)73%very high
September Weather16°C (61°F)83 mm (3.3 inches)78%high
October Weather8°C (47°F)109 mm (4.3 inches)84%moderate
November Weather0°C (32°F)50 mm (2.0 inches)89%moderate
December Weather-5°C (23°F)52 mm (2.1 inches)87%low

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