Shell Rock, IA 50670 Frost Dates
Frost dates for Shell Rock, IA, ZIP 50670
The last spring frost here typically falls around 04/27, about 242 days from today. The first fall frost typically arrives around 10/10, about 165 frost-free days later.
Zone 5a (-20 to -15°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 Shell Rock, not a forecast for this year.
What to do before the first frost
Zone 5a around Shell Rock 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 Shell Rock's last frost
04/27 is the middle of 30 years of NOAA records, not a promise. Plant by 04/11 and you're betting against frost in roughly 9 years out of 10. 05/10 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Shell Rock compares
Shell Rock's growing season runs about 165 days, ranking 30,636 of 40,283 US ZIP codes measured here, longest to shortest. Within IA, it ranks 514 of 1,042.
Learn more
the frost range explains how to read the range around Shell Rock's dates instead of trusting one, and local microclimates explains what one yard in Shell Rock can differ from the 50670 normal.