Florissant, MO 63031 Frost Dates
When can you plant in Florissant, MO?
Typically, the last spring freeze lands around 04/02, roughly 217 days out. The first fall frost typically arrives around 11/04, about 215 frost-free days later.
Zone 7a (0 to 5°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 Florissant, not a forecast for this year.
What to do before the first frost
About 10 weeks of growing season left in Florissant before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/02 isn't a guarantee
04/02 is the middle of 30 years of NOAA records, not a promise. Plant by 03/17 and you're betting against frost in roughly 9 years out of 10. 04/17 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Florissant compares
Florissant's growing season runs about 215 days, ranking 14,021 of 40,283 US ZIP codes measured here, longest to shortest. Within MO, it ranks 107 of 1,129.
Learn more
zone vs. frost date covers why Zone 7a and Florissant's frost date answer different questions. the frost range covers how to read the range around Florissant's dates instead of trusting one.