Royal, IA 51357 Frost Dates
When can you plant in Royal, IA?
The last spring frost here typically falls around 05/02, about 247 days from today. The first fall frost typically arrives around 10/02, about 154 frost-free days later.
Royal 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
About 5 weeks of growing season left in Royal before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/02 isn't a guarantee
05/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/17 and you're betting against frost in roughly 9 years out of 10. 05/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Royal compares
About 154 days separate Royal's last and first frost, putting it 34,429 of 40,283 ZIP codes nationally. Within IA, it ranks 906 of 1,042.
Learn more
the frost range covers how to read the range around Royal's dates instead of trusting one. local microclimates covers what one yard in Royal can differ from the 51357 normal.