42.3584°N/71.0598°W
When to plant in Boston
Massachusetts, United States · Continental, hot summer (Köppen Dfa)
Last spring frost · safe
Apr 15
~10% frost risk · typical Apr 4
First fall frost · safe
Oct 31
~10% frost risk · typical Nov 9
Frost-free days
220
Apr 4 → Nov 9
Climate zone
Continental, hot summer
Köppen Dfa
89/100 confidence
◇ Station-based
The frost date shown is the safe date (~10% frost risk); the typical median is shown alongside. Your microclimate can shift things ±1–2 weeks.
The growing year
Frost-bounded season with crops mapped onto the 12-month axis.
Frost risk Growing Harvest
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
FROST
FROST
GROWING SEASON — 220 DAYS
APR 4
NOV 9
Full crop calendar
Same climate — Continental, hot summer
Source: Curated · based on NOAA GHCN-Daily 1991–2020 normal · Köppen–Geiger classification (Beck et al. 2023) · crop windows from FAO ECOCROP references. How we calculate this →
Also see frost dates for Boston.