St. Louis, MO 63110 Frost Dates
St. Louis, MO: when does the frost end?
Around 04/01 is the usual last spring frost, about 216 days away. Fall's first freeze usually shows up around 11/04, roughly 218 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 10 weeks until St. Louis's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/01 isn't a guarantee
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
At roughly 218 frost-free days, St. Louis places 13,147 of 40,283 ZIP codes in this dataset. Within MO, it ranks 51 of 1,129.
Learn more
Before leaning on 63110's figures: zone vs. frost date explains why Zone 7a and St. Louis's frost date answer different questions, while the frost range explains how to read the range around St. Louis's dates instead of trusting one.