Plainfield, IA 50666 Frost Dates
50666, near Plainfield, IA: the frost window
Typically, the last spring freeze lands around 04/29, roughly 244 days out. Fall's first freeze usually shows up around 10/09, roughly 162 days after the last spring frost.
Plainfield sits in USDA Zone 5a (-20 to -15°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
Plainfield's growing season runs out in roughly 6 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
04/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/09 and only about 1 year in 10 sees frost after that.
Plainfield against the rest of the dataset
Plainfield's growing season runs about 162 days, ranking 31,852 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 726 of 1,042.
Learn more
Two guides worth reading on 50666: zone vs. frost date, on why Zone 5a and Plainfield's frost date answer different questions, and the frost range, on how to read the range around Plainfield's dates instead of trusting one.