North Washington, IA 50661 Frost Dates
When can you plant in North Washington, IA?
Typically, the last spring freeze lands around 05/02, roughly 247 days out. The first fall frost typically arrives around 10/05, about 155 frost-free days later.
North Washington 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 North Washington before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around North Washington's last frost
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. 05/14 is the safer bet, historically only a 1-in-10 chance of frost that late.
How North Washington compares
About 155 days separate North Washington's last and first frost, putting it 34,180 of 40,283 ZIP codes nationally. Within IA, it ranks 889 of 1,042.
Learn more
zone vs. frost date covers why Zone 5a and North Washington's frost date answer different questions. the frost range covers how to read the range around North Washington's dates instead of trusting one.