Chelmsford (MA) Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Chelmsford.
Climate overview of Chelmsford
Chelmsford, Massachusetts, United States of America, experiences significant temperature variation throughout the year. Summers bring daytime highs of 29°C (84°F) in July, while winters cool to 2°C (36°F) in January.
With around 1278 mm (50 in) of annual rain/snowfall, Chelmsford has a notably wet climate. However, this rain/snowfall is not evenly distributed, the city has warm summers and very cold winters. The wettest month is October. May is the sunniest month, averaging 10.0 hours of sunshine per day.
Chelmsford Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Chelmsford - and find the best time to visit.
Monthly Temperature in Chelmsford
Depending on the time of the year, temperatures range from comfortable to very cold in Chelmsford. Average daytime temperatures reach a comfortable 29°C (84°F) in July. In January, the coolest month of the year, temperatures drop to a very cold 2°C (36°F).
At night, temperatures range from around 17°C (63°F) in July to -9°C (16°F) in January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Chelmsford
Chelmsford has a relatively rain/snowy climate with high precipitation levels, averaging 1278 mm (50 in) of rain/snowfall annually. Despite minor fluctuations, Chelmsford enjoys fairly consistent precipitation throughout the year. In October, you can expect around 129 mm (5.1 in) of precipitation, while in January, Chelmsford receives about 88 mm (3.5 in). For more details, please visit our Chelmsford Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Chelmsford
Chelmsford can be enjoyed more throughout the sunniest month of May under a blue sky, with approximately 10.0 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 4.7 hours of sunlight per day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Daily percentage of sunshine
Humidity in Chelmsford by Month
The relative humidity is high throughout the year in Chelmsford.
The city experiences its highest humidity in August, reaching 72%. In February, the humidity drops to its lowest level at 62%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Best Time to Visit Chelmsford
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: September
- Warmest weather: July and August
- Most sunshine: May and July
- Seasonal pattern: Warm summers and very cold winters
- Coldest conditions: January, with freezing nights around -9°C (16°F).
Frequently asked questions about the climate in Chelmsford
What is the best time to visit Chelmsford?
September typically offers the most optimal weather in Chelmsford. In contrast, January, February, March and December tend to have less optimal conditions. Chelmsford has warm summers and very cold winters.
What temperatures can I expect in Chelmsford?
Daytime highs range from 2°C (36°F) in January to 29°C (84°F) in July. Nighttime lows range from -9°C (16°F) to 17°C (63°F). Temperatures vary considerably through the year.
How much rain does Chelmsford get?
Annual rainfall is around 1278 mm (50 in). October is the wettest month with 129 mm (5.1 in), while January is the driest with 88 mm (3.5 in).
How sunny is Chelmsford?
Chelmsford receives around 2,665 hours of sunshine per year. May is the sunniest month with 301 hours, while December is the cloudiest with just 141 hours. Overall, Chelmsford enjoys abundant sunshine.
Chelmsford 3-Day Forecast
Chelmsford on the map
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