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September Weather in Falmouth, United States

Last updated: June 24, 2025

In September, the average temperature in Falmouth, United States hovers around 23°C (73°F), making it a delightful time for outdoor activities. Expect lows of 8°C (46°F) and highs reaching up to 37°C (99°F), offering a comfortable range for all preferences. However, be prepared for occasional rain, with 91 mm (3.6 in) of precipitation expected over about 11 days. The average humidity is a moderate 68%, ensuring a pleasant atmosphere throughout the month.

September Temperature in Falmouth

In September in Falmouth, the average temperature is 23°C (73°F). Maximums can reach 37°C (99°F) and minimums can be as low as 8°C (46°F). This diverse temperature range makes Falmouth an ideal destination for travelers looking to enjoy both warm and cool experiences during their visit.

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

The chart illustrates September temperature patterns in Falmouth, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Falmouth, September typically has an average temperature of 23°C (73°F), with highs reaching up to 37°C (99°F) and lows dropping to around 8°C (46°F).
JanFebMarAprMayJunJulAugSepOctNovDec394348586876817873634943
Data source: Temperature data for Falmouth 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 Falmouth

In Falmouth in September, the precipitation amount is 91 mm (3.6 in) over a period of 11 days.

September Precipitation Trends in Falmouth

The chart displays monthly precipitation patterns in Falmouth, 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 Falmouth, September typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec62907610110910991148911097788
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Falmouth

In Falmouth in September humidity is 68%. With an average temperature of 23°C (73°F), this humidity feels like a soft blanket wrapping around you, making every step outside feel a bit heavier, but offering a warm embrace that encourages leisurely exploration and a relaxed pace for travel.

September Average Humidity in Falmouth

This chart illustrates the average monthly humidity levels in Falmouth, 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 Falmouth is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%84%78%79%70%59%68%80%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Falmouth

In Falmouth 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 Falmouth.

Maximum UV Index Levels in Falmouth for September

The chart shows the monthly maximum UV Index (UVI) for Falmouth 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 Falmouth typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098753
Data source: Falmouth 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 Falmouth Compares to Other Months

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

This table compares monthly weather conditions in Falmouth, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather4°C (39°F)62 mm (2.4 inches)86%moderate
February Weather6°C (43°F)90 mm (3.6 inches)86%moderate
March Weather9°C (49°F)76 mm (3.0 inches)86%high
April Weather15°C (59°F)101 mm (4.0 inches)84%very high
May Weather20°C (68°F)109 mm (4.3 inches)78%very high
June Weather24°C (76°F)109 mm (4.3 inches)79%very high
July Weather27°C (81°F)91 mm (3.6 inches)70%very high
August Weather26°C (78°F)148 mm (5.8 inches)59%very high
September Weather23°C (73°F)91 mm (3.6 inches)68%very high
October Weather17°C (63°F)109 mm (4.3 inches)80%high
November Weather9°C (49°F)77 mm (3.0 inches)86%moderate
December Weather6°C (43°F)88 mm (3.5 inches)85%moderate

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