Sumner, IA 50674 Frost Dates
Frost dates for Sumner, IA, ZIP 50674
Around 04/29 is the usual last spring frost, about 244 days away. The first fall frost typically arrives around 10/09, about 162 frost-free days later.
Sumner 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.
What to do before the first frost
Zone 5a around Sumner has about 6 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.
The actual range around Sumner's last frost
04/29 is the middle of 30 years of NOAA records, not a promise. Plant by 04/14 and you're betting against frost in roughly 9 years out of 10. 05/09 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Sumner compares
At roughly 162 frost-free days, Sumner places 31,758 of 40,283 ZIP codes in this dataset. Within IA, it ranks 700 of 1,042.
Learn more
the frost range explains how to read the range around Sumner's dates instead of trusting one, and local microclimates explains what one yard in Sumner can differ from the 50674 normal.