St. Louis, MO 63166 Frost Dates
Frost dates for St. Louis, MO, ZIP 63166
The last spring frost here typically falls around 04/01, about 216 days from today. The first fall frost typically arrives around 11/04, about 218 frost-free days later.
The USDA Plant Hardiness Zone Map puts St. Louis in Zone 7a (0 to 5°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
Zone 7a around St. Louis has about 10 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
The actual range around St. Louis's last frost
04/01 is the middle of 30 years of NOAA records, not a promise. Plant by 03/14 and you're betting against frost in roughly 9 years out of 10. 04/18 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Louis compares
St. Louis's growing season runs about 218 days, ranking 13,158 of 40,283 US ZIP codes measured here, longest to shortest. Within MO, it ranks 62 of 1,129.
Learn more
local microclimates explains what one yard in St. Louis can differ from the 63166 normal, and zone vs. frost date explains why Zone 7a and St. Louis's frost date answer different questions.