Riley, KS 66531 Frost Dates
Frost dates for Riley, KS, ZIP 66531
Typically, the last spring freeze lands around 04/22, roughly 237 days out. The first fall frost typically arrives around 10/20, about 179 frost-free days later.
Riley sits in USDA Zone 6b (-5 to 0°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.
What to do before the first frost
Zone 6b around Riley has about 8 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
04/22 is the middle of 30 years of NOAA records, not a promise. Plant by 04/08 and you're betting against frost in roughly 9 years out of 10. 05/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Riley compares
About 179 days separate Riley's last and first frost, putting it 25,401 of 40,283 ZIP codes nationally. Within KS, it ranks 554 of 745.
Learn more
zone vs. frost date explains why Zone 6b and Riley's frost date answer different questions, and the frost range explains how to read the range around Riley's dates instead of trusting one.