Topeka, KS 66603 Frost Dates
66603, near Topeka, KS: the frost window
Typically, the last spring freeze lands around 04/16, roughly 231 days out. Fall's first freeze usually shows up around 10/22, roughly 189 days after the last spring frost.
Zone 6b (-5 to 0°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 Topeka, not a forecast for this year.
Stretching the season past the first frost
Topeka's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/01 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/27 and only about 1 year in 10 sees frost after that.
Topeka against the rest of the dataset
At roughly 189 frost-free days, Topeka places 21,363 of 40,283 ZIP codes in this dataset. Within KS, it ranks 304 of 745.
Learn more
Two guides worth reading on 66603: local microclimates, on what one yard in Topeka can differ from the 66603 normal, and zone vs. frost date, on why Zone 6b and Topeka's frost date answer different questions.