Climate averages 1991–2020

Nashua weather
in September.

A warm, moderately wet month: the 4th warmest and the joint 5th driest of the year. Meets the pleasant-weather rule

Long-term climate patterns, not a forecast for a particular trip.

Average high 22.5°C Daytime mean, September
Average low 13.4°C Night-time mean, September
Rainfall 86 mm 8 days with ≥1 mm
Daylight 13 h Sunrise to sunset, per day
Every month in Nashua · average highYear overview

September is a warm month in Nashua: daytime highs average 22.5°C and nights cool to about 13.4°C. By daytime temperature it is the 4th warmest of the 12 months.

Expect about 86 mm of rain on roughly 8 days, which makes September a moderately wet month (the joint 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 32 min on an average September day.

The nearest other city in this atlas is Lowell (19 km away). In September its highs average 22.6°C, about as warm as Nashua, with 84 mm of rain.

Among the 498 cities listed in the United States, Nashua ranks joint 433rd of 498 for the warmest September highs and joint 314th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Nashua is 4.4°C cooler than that mean.

From September to October, average highs fall by 7.0°C to 15.5°C, and monthly rainfall rises from 86 mm to 97 mm.

The annual picture

September in context

30-year average
Average highAverage low°C
Average daily high and low temperatures by month The same values are available in the monthly table below. Lines show mean daily maxima and minima, not a forecast interval. -15-10-5051015202530 JanFebMarAprMayJunJulAugSepOctNovDec

Monthly precipitation

Average total · mm
Average monthly precipitation totalsEach bar is a mean monthly total over 1991–2020. Full numbers are in the table. JanFebMarAprMayJunJulAugSepOctNovDec 1500

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Nashua climate table

1991–2020
Monthly climate averages for Nashua, 1991–2020
MonthAverage highHigh / lowAverage lowPrecipitation mm/monthWet days ≥1 mm/dayDaylight hours/dayDay­light h/day
January 0.4°C-8.4°C-8.4°C809.69.49 h
February 2.0°C-7.5°C-7.5°C768.510.511 h
March 6.4°C-3.2°C-3.2°C10310.911.912 h
April 13.3°C3.0°C3.0°C9410.513.413 h
May 19.3°C9.1°C9.1°C8110.814.615 h
June 24.6°C14.7°C14.7°C9010.815.315 h
July 27.9°C18.0°C18.0°C8610.315.015 h
August 26.9°C17.3°C17.3°C859.613.914 h
September, selected 22.5°C13.4°C13.4°C868.012.513 h
October 15.5°C7.2°C7.2°C979.311.111 h
November 9.0°C1.5°C1.5°C869.49.810 h
December 3.3°C-4.2°C-4.2°C10510.39.19 h

Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

September in nearby cities

Distance from Nashua

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Nashua) is explained once on the Nashua year overview and on the Sources, method and limits page.