Carter Lake, IA 51510 Frost Dates
51510, near Carter Lake, IA: the frost window
Typically, the last spring freeze lands around 04/18, roughly 233 days out. Fall's first freeze usually shows up around 10/21, roughly 185 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Carter Lake in Zone 6a (-10 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
Carter Lake'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.
Why 04/18 isn't a guarantee
04/18 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/30 and only about 1 year in 10 sees frost after that.
Carter Lake against the rest of the dataset
At roughly 185 frost-free days, Carter Lake places 23,150 of 40,283 ZIP codes in this dataset. Within IA, it ranks 35 of 1,042.
Learn more
Two guides worth reading on 51510: the frost range, on how to read the range around Carter Lake's dates instead of trusting one, and local microclimates, on what one yard in Carter Lake can differ from the 51510 normal.