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September Weather in Lowell, United States

Last updated: June 24, 2025

In September, the average temperature in Lowell, United States hovers around 20°C (69°F). Expect a delightful range, with minimums dipping to 4°C (40°F) and maximums soaring to 34°C (94°F). However, be prepared for some rain, as 74 mm (2.9 in) of precipitation may fall over 9 days. With an average humidity of 80%, you’ll find the air quite moist. Enjoy the varied climate!

September Temperature in Lowell

In September in Lowell, the average temperature is 20°C (69°F). Maximums can reach 34°C (94°F), and minimums can be as low as 4°C (40°F). This makes it a great time to explore Lowell, as you'll experience mild weather with the potential for warm days and cooler nights.

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

The chart illustrates September temperature patterns in Lowell, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Lowell, September typically has an average temperature of 20°C (69°F), with highs reaching up to 34°C (94°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec272940506273767468554034
Data source: Temperature data for Lowell 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 Lowell

In Lowell in September, the precipitation amount is 74 mm (2.9 in), which occurs over a span of 9 days.

September Precipitation Trends in Lowell

The chart displays monthly precipitation patterns in Lowell, 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 Lowell, September typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec707198118163120109101741326657
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Lowell

In Lowell in September, humidity is 80%. With an average temperature of 20°C (69°F), this humidity feels like a warm blanket enveloping you, making every step slightly more challenging as you navigate the air that clings to your skin, often leaving you longing for a cool breeze while exploring the sights.

September Average Humidity in Lowell

This chart illustrates the average monthly humidity levels in Lowell, 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 Lowell is approximately 80%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%83%84%85%79%82%80%81%80%82%88%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Lowell

In Lowell 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 Lowell.

Maximum UV Index Levels in Lowell for September

The chart shows the monthly maximum UV Index (UVI) for Lowell 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 Lowell typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: Lowell 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 Lowell Compares to Other Months

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

This table compares monthly weather conditions in Lowell, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (27°F)70 mm (2.8 inches)82%moderate
February Weather-2°C (29°F)71 mm (2.8 inches)83%moderate
March Weather5°C (41°F)98 mm (3.9 inches)84%high
April Weather10°C (50°F)118 mm (4.6 inches)85%very high
May Weather17°C (62°F)163 mm (6.4 inches)79%very high
June Weather23°C (73°F)120 mm (4.7 inches)82%very high
July Weather24°C (76°F)109 mm (4.3 inches)80%very high
August Weather23°C (74°F)101 mm (4.0 inches)81%very high
September Weather20°C (69°F)74 mm (2.9 inches)80%very high
October Weather13°C (56°F)132 mm (5.2 inches)82%high
November Weather4°C (40°F)66 mm (2.6 inches)88%moderate
December Weather1°C (34°F)56 mm (2.2 inches)84%low

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