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September Weather in Plymouth, United States

Last updated: June 24, 2025

In September, the average temperature in Plymouth, United States is a pleasant 19°C (66°F), with fluctuations ranging from a chilly 2°C (36°F) to a warm 34°C (93°F). The region experiences 62 mm (2.4 in) of precipitation spread over about 10 days, contributing to an average humidity level of 80%.

September Temperature in Plymouth

In September in Plymouth, the average temperature is 19°C (66°F). Maximums can reach 34°C (93°F), while minimums can drop to as low as 2°C (36°F). Travelers should be prepared for a range of temperatures, making layers essential for comfort during the day and cooler evenings.

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

The chart illustrates September temperature patterns in Plymouth, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Plymouth, September typically has an average temperature of 19°C (66°F), with highs reaching up to 34°C (93°F) and lows dropping to around 2°C (36°F).
JanFebMarAprMayJunJulAugSepOctNovDec272837476070757366543933
Data source: Temperature data for Plymouth 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 Plymouth

In Plymouth in September, the total precipitation amount is 62 mm (2.4 in) over a period of 10 days.

September Precipitation Trends in Plymouth

The chart displays monthly precipitation patterns in Plymouth, 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 Plymouth, September typically receives around 62 mm (2.4 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec6466738711785927462987754
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Plymouth

In Plymouth in September humidity is 80%. With an average temperature of 19°C (66°F), this humidity feels like a warm, thick blanket wrapping around you, making outdoor activities feel more strenuous and sticky, which can ultimately dampen the experience of traveling.

September Average Humidity in Plymouth

This chart illustrates the average monthly humidity levels in Plymouth, 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 Plymouth is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%85%86%80%80%80%81%80%84%90%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Plymouth

In Plymouth 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 Plymouth.

Maximum UV Index Levels in Plymouth for September

The chart shows the monthly maximum UV Index (UVI) for Plymouth 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 Plymouth typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24599101097542
Data source: Plymouth 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 Plymouth Compares to Other Months

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

This table compares monthly weather conditions in Plymouth, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)64 mm (2.5 inches)88%low
February Weather-2°C (29°F)66 mm (2.6 inches)87%moderate
March Weather3°C (38°F)73 mm (2.9 inches)85%moderate
April Weather8°C (47°F)86 mm (3.4 inches)86%very high
May Weather15°C (60°F)117 mm (4.6 inches)80%very high
June Weather21°C (71°F)85 mm (3.3 inches)80%very high
July Weather24°C (75°F)91 mm (3.6 inches)80%very high
August Weather23°C (73°F)74 mm (2.9 inches)80%very high
September Weather19°C (66°F)62 mm (2.4 inches)80%high
October Weather12°C (55°F)98 mm (3.9 inches)84%moderate
November Weather4°C (40°F)77 mm (3.0 inches)89%moderate
December Weather0°C (33°F)54 mm (2.1 inches)86%low

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