Alton, MO 65778 Frost Dates
Alton, MO: when does the frost end?
The last spring frost here typically falls around 04/17, about 232 days from today. Fall's first freeze usually shows up around 10/21, roughly 187 days after the last spring frost.
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 Alton, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Alton's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/01 and only about 1 year in 10 sees frost after that.
Alton against the rest of the dataset
Alton's growing season runs about 187 days, ranking 22,521 of 40,283 US ZIP codes measured here, longest to shortest. Within MO, it ranks 846 of 1,129.
Learn more
Before leaning on 65778's figures: the frost range explains how to read the range around Alton's dates instead of trusting one, while local microclimates explains what one yard in Alton can differ from the 65778 normal.