September Weather in Lowell, United States

Last updated: June 24, 2025

In Lowell, United States, the average temperature in September hovers around 21°C (70°F), creating a pleasant climate for both locals and visitors. However, temperatures can vary significantly, with lows of 5°C (42°F) and highs reaching 36°C (98°F). Expect some precipitation, with an average of 107 mm (4.2 in) spread across 9 days, and a notable average humidity of 73% that can make the air feel a bit warmer.

September Temperature in Lowell

In September in Lowell, the average temperature is 21°C (70°F). Maximums can reach 36°C (98°F) and minima can be as low as 5°C (42°F). This range makes it essential for travelers to pack appropriately to enjoy the diverse weather conditions.

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 21°C (70°F), with highs reaching up to 36°C (98°F) and lows dropping to around 5°C (42°F).

Data source: Temperature data for Lowell generated using information from the Copernicus Climate Change Service.

September Precipitation in Lowell

In Lowell in September, the precipitation amount is 107 mm (4.2 in), occurring 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 107 mm (4.2 inches) of precipitation spread over approximately 9 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Lowell

In Lowell in September, humidity is 73%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace that can make outdoor activities feel sweltering, so it's essential to stay hydrated and take breaks in the shade while exploring.

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 73%, offering insight into how humid the weather typically is during this month.

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.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	1°C (34°F)	91 mm (3.6 inches)	88%	moderate
February Weather	3°C (38°F)	121 mm (4.8 inches)	88%	moderate
March Weather	7°C (45°F)	116 mm (4.6 inches)	88%	high
April Weather	12°C (54°F)	146 mm (5.7 inches)	86%	very high
May Weather	18°C (65°F)	143 mm (5.6 inches)	82%	very high
June Weather	22°C (72°F)	164 mm (6.5 inches)	84%	very high
July Weather	25°C (76°F)	122 mm (4.8 inches)	82%	very high
August Weather	23°C (74°F)	110 mm (4.3 inches)	73%	very high
September Weather	21°C (70°F)	107 mm (4.2 inches)	73%	very high
October Weather	15°C (59°F)	116 mm (4.6 inches)	81%	high
November Weather	7°C (44°F)	86 mm (3.4 inches)	89%	moderate
December Weather	3°C (39°F)	115 mm (4.5 inches)	86%	moderate