Watertown, MA 02476 Frost Dates
When can you plant in Watertown, MA?
Around 04/28 is the usual last spring frost, about 243 days away. The first fall frost typically arrives around 10/10, about 165 frost-free days later.
The USDA Plant Hardiness Zone Map puts Watertown in Zone 6b (-5 to 0°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 6 weeks of growing season left in Watertown before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/28 is the middle of 30 years of NOAA records, not a promise. Plant by 04/13 and you're betting against frost in roughly 9 years out of 10. 05/12 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Watertown compares
Watertown's growing season runs about 165 days, ranking 30,508 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 405 of 712.
Learn more
local microclimates covers what one yard in Watertown can differ from the 02476 normal. zone vs. frost date covers why Zone 6b and Watertown's frost date answer different questions.