September Weather in Nashua, United States

Last updated: June 24, 2025

In September, the average temperature in Nashua, United States is a comfortable 18°C (65°F). However, temperatures can fluctuate, with lows of 2°C (36°F) and highs reaching 33°C (92°F). Be prepared for 114 mm (4.5 in) of precipitation spread over about 11 days, and note that humidity averages around 75%, making the air feel quite moist.

September Temperature in Nashua

In September, in Nashua, the average temperature is 18°C (65°F). The maximum can reach 33°C (92°F), while the minimum can be as low as 2°C (36°F). This temperature range makes Nashua an ideal destination for travelers seeking both warm days and cool nights.

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

The chart illustrates September temperature patterns in Nashua, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Nashua, September typically has an average temperature of 18°C (65°F), with highs reaching up to 33°C (92°F) and lows dropping to around 2°C (36°F).

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

September Precipitation in Nashua

In Nashua in September, the total precipitation amount is 114 mm (4.5 in) spread over 11 days.

September Precipitation Trends in Nashua

The chart displays monthly precipitation patterns in Nashua, 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 Nashua, September typically receives around 114 mm (4.5 inches) of precipitation spread over approximately 11 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Nashua

In Nashua in September, humidity is 75%. With an average temperature of 18°C (65°F), this humidity feels like a warm, enveloping blanket that can make outdoor exploration feel a bit stifling, potentially leading to discomfort during travel activities.

September Average Humidity in Nashua

This chart illustrates the average monthly humidity levels in Nashua, 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 Nashua is approximately 75%, 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 Nashua

In Nashua 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 Nashua.

Maximum UV Index Levels in Nashua for September

The chart shows the monthly maximum UV Index (UVI) for Nashua 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 Nashua typically reaches 8, which falls under the very high exposure category.

Data source: Nashua 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 Nashua Compares to Other Months

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

This table compares monthly weather conditions in Nashua, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-7°C (19°F)	38 mm (1.5 inches)	82%	moderate
February Weather	-7°C (19°F)	50 mm (2.0 inches)	84%	moderate
March Weather	2°C (36°F)	72 mm (2.8 inches)	80%	moderate
April Weather	8°C (46°F)	72 mm (2.8 inches)	81%	very high
May Weather	16°C (60°F)	163 mm (6.4 inches)	74%	very high
June Weather	22°C (72°F)	128 mm (5.0 inches)	80%	extreme
July Weather	23°C (74°F)	92 mm (3.6 inches)	80%	very high
August Weather	21°C (71°F)	119 mm (4.7 inches)	77%	very high
September Weather	18°C (65°F)	114 mm (4.5 inches)	75%	very high
October Weather	10°C (50°F)	130 mm (5.1 inches)	80%	moderate
November Weather	2°C (35°F)	50 mm (2.0 inches)	87%	moderate
December Weather	-2°C (28°F)	37 mm (1.4 inches)	83%	moderate