Waltham, MA 02493 Frost Dates
When can you plant in Waltham, MA?
Typically, the last spring freeze lands around 04/26, roughly 241 days out. The first fall frost typically arrives around 10/12, about 169 frost-free days later.
Waltham sits in USDA Zone 6b (-5 to 0°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 6 weeks of growing season left in Waltham before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Waltham's last frost
04/26 is the middle of 30 years of NOAA records, not a promise. Plant by 04/14 and you're betting against frost in roughly 9 years out of 10. 05/09 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Waltham compares
Waltham's growing season runs about 169 days, ranking 29,310 of 40,283 US ZIP codes measured here, longest to shortest. Within MA, it ranks 347 of 712.
Learn more
local microclimates covers what one yard in Waltham can differ from the 02493 normal. zone vs. frost date covers why Zone 6b and Waltham's frost date answer different questions.