St. Louis, MO 63163 Frost Dates
63163, near St. Louis, MO: the frost window
Typically, the last spring freeze lands around 04/01, roughly 216 days out. Fall's first freeze usually shows up around 11/04, roughly 218 days after the last spring frost.
St. Louis sits in USDA Zone 7a (0 to 5°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.
Stretching the season past the first frost
St. Louis's growing season runs out in roughly 10 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around St. Louis's last frost
04/01 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/18 and only about 1 year in 10 sees frost after that.
St. Louis against the rest of the dataset
St. Louis's growing season runs about 218 days, ranking 13,156 of 40,283 US ZIP codes measured here, longest to shortest. Within MO, it ranks 60 of 1,129.
Learn more
Two guides worth reading on 63163: local microclimates, on what one yard in St. Louis can differ from the 63163 normal, and zone vs. frost date, on why Zone 7a and St. Louis's frost date answer different questions.