Martinsburg, IA 52568 Frost Dates
Frost dates for Martinsburg, IA, ZIP 52568
Typically, the last spring freeze lands around 04/23, roughly 238 days out. The first fall frost typically arrives around 10/14, about 172 frost-free days later.
The USDA Plant Hardiness Zone Map puts Martinsburg in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 5b around Martinsburg has about 7 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 Martinsburg's last frost
04/23 is the middle of 30 years of NOAA records, not a promise. Plant by 04/09 and you're betting against frost in roughly 9 years out of 10. 05/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Martinsburg compares
About 172 days separate Martinsburg's last and first frost, putting it 28,541 of 40,283 ZIP codes nationally. Within IA, it ranks 281 of 1,042.
Learn more
local microclimates explains what one yard in Martinsburg can differ from the 52568 normal, and zone vs. frost date explains why Zone 5b and Martinsburg's frost date answer different questions.