Waltham, MA 02453 Frost Dates
When can you plant in Waltham, MA?
Typically, the last spring freeze lands around 04/19, roughly 234 days out. The first fall frost typically arrives around 10/23, about 185 frost-free days later.
Zone 6b (-5 to 0°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Waltham, not a forecast for this year.
What to do before the first frost
About 8 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
04/19 is the middle of 30 years of NOAA records, not a promise. Plant by 04/06 and you're betting against frost in roughly 9 years out of 10. 05/03 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Waltham compares
At roughly 185 frost-free days, Waltham places 23,047 of 40,283 ZIP codes in this dataset. Within MA, it ranks 192 of 712.
Learn more
zone vs. frost date covers why Zone 6b and Waltham's frost date answer different questions. the frost range covers how to read the range around Waltham's dates instead of trusting one.