Chelmsford (MA) Temperature by Month
Chelmsford in Massachusetts, United States of America sees significant seasonal temperature differences, with daytime highs between 2°C (36°F) in February and 29°C (84°F) in July, averaging 16°C (61°F) annually. Explore the full monthly breakdown below.
Chelmsford Monthly Temperatures
Visitors to Chelmsford will encounter a climate influenced by big temperature differences across the year. Nighttime temperatures range from 17°C (63°F) in July to -9°C (16°F) in February.
The chart below illustrates the average maximum day and minimum night temperatures in Chelmsford by month:
The coldest point of the day usually falls between 4 AM and 6 AM, with temperatures peaking around 3 PM. July, the city's warmest month, gets 300 hours of sunshine.
The chart below shows the average temperature throughout the year:
Temperature: Chelmsford vs the United States of America
The map below shows the annual temperature across the United States of America. You can also select individual months if you want to compare a specific time of year.
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Chelmsford vs World: Temperature Compared
Chelmsford's average annual maximum temperature is 16°C (61°F). To put that in context, here's how it compares to a few well-known destinations:
Lisbon, Portugal averages 21°C (70°F) annually — warm summers, mild winters, and rain mainly in the cooler months.
Toronto, Canada averages 13°C (55°F) annually, with cold snowy winters balanced by genuinely warm summers.
Shanghai, China averages 21°C (70°F) a year, with warm summers, mild winters, and a noticeable spring and autumn.
Perth, Australia averages 25°C (77°F) annually, with a classic Mediterranean climate — hot dry summers and mild wet winters.
What Does the Temperature Feel Like in Chelmsford?
Temperature alone doesn't tell the whole story — humidity plays a big role in how warm or cold it actually feels. High humidity in summer makes the heat feel more intense, particularly once temperatures climb above 25°C. In winter, the same humidity can make cold air feel sharper than the thermometer suggests.
In the cooler months, when temperatures drop below 10°C, high humidity makes the cold feel more cutting than it would in dry conditions.
In Chelmsford, February is the coolest month, with average highs of 3°C (37°F) and humidity around 62% — considered high. In July, the warmest month, temperatures average 29°C (84°F) with 71% humidity — conditions that feel high. For a full picture, see our humidity page.
Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.
The readings come from a range of sources — land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.
Seasonal temperature shifts influence more than just how warm it feels — they also drive changes in rainfall, cloud cover, and wind patterns throughout the year.
Warmer air holds more moisture, which tends to mean heavier or more frequent rain during the warmer months. When temperatures drop in winter, any precipitation that does fall is more likely to come as snow or sleet, though in Chelmsford this rarely lasts long on the ground.
For more on Chelmsford's weather — including monthly rainfall, sunshine hours, and humidity — visit our Chelmsford climate page.
