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September Weather in Casco, United States

Last updated: June 24, 2025

In September, the average temperature in Casco, United States is a pleasant 17°C (64°F). Expect a range from a cool 4°C (39°F) at its lowest to a warm 31°C (87°F) at its peak. With 62 mm (2.4 in) of precipitation spread over 7 days, be prepared for occasional rain. On top of that, the average humidity sits at 71%, ensuring a lush and vibrant atmosphere.

September Temperature in Casco

In September in Casco, the average temperature is 17°C (64°F). Maximum temperatures can reach 31°C (87°F), while the minimum can drop as low as 4°C (39°F). It's an ideal time to explore Casco with its mild climate and pleasant conditions for outdoor activities.

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

The chart illustrates September temperature patterns in Casco, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Casco, September typically has an average temperature of 17°C (64°F), with highs reaching up to 31°C (87°F) and lows dropping to around 4°C (39°F).
JanFebMarAprMayJunJulAugSepOctNovDec232531435465717163523928
Data source: Temperature data for Casco 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 Casco

In Casco in September, the total precipitation amount is 62 mm (2.4 in) observed over a span of 7 days.

September Precipitation Trends in Casco

The chart displays monthly precipitation patterns in Casco, 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 Casco, September typically receives around 62 mm (2.4 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec79857211274731397962117102110
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Casco

In Casco in September humidity is 71%. With an average temperature of 17°C (64°F), this humidity feels like a warm, enveloping embrace that can make travel feel a bit sticky, yet still pleasant as you explore the sights with a gentle sheen of perspiration.

September Average Humidity in Casco

This chart illustrates the average monthly humidity levels in Casco, 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 Casco is approximately 71%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%84%82%80%72%72%67%66%71%79%84%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Casco

In Casco 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 Casco.

Maximum UV Index Levels in Casco for September

The chart shows the monthly maximum UV Index (UVI) for Casco 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 Casco typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2458910987532
Data source: Casco 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 Casco Compares to Other Months

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

This table compares monthly weather conditions in Casco, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-5°C (23°F)79 mm (3.1 inches)86%low
February Weather-4°C (25°F)85 mm (3.3 inches)84%moderate
March Weather0°C (32°F)72 mm (2.9 inches)82%moderate
April Weather6°C (43°F)112 mm (4.4 inches)80%very high
May Weather12°C (54°F)74 mm (2.9 inches)72%very high
June Weather19°C (66°F)73 mm (2.9 inches)72%very high
July Weather22°C (72°F)139 mm (5.5 inches)67%very high
August Weather21°C (71°F)79 mm (3.1 inches)66%very high
September Weather17°C (64°F)62 mm (2.4 inches)71%high
October Weather11°C (52°F)117 mm (4.6 inches)78%moderate
November Weather4°C (39°F)102 mm (4.0 inches)84%moderate
December Weather-2°C (28°F)110 mm (4.3 inches)81%low

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