Washington, MO 63090 Frost Dates
When can you plant in Washington, MO?
Around 04/08 is the usual last spring frost, about 223 days away. The first fall frost typically arrives around 10/25, about 199 frost-free days later.
Zone 6b (-5 to 0°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 Washington, not a forecast for this year.
What to do before the first frost
About 8 weeks of growing season left in Washington before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/08 is the middle of 30 years of NOAA records, not a promise. Plant by 03/24 and you're betting against frost in roughly 9 years out of 10. 04/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Washington compares
About 199 days separate Washington's last and first frost, putting it 18,048 of 40,283 ZIP codes nationally. Within MO, it ranks 417 of 1,129.
Learn more
zone vs. frost date covers why Zone 6b and Washington's frost date answer different questions. the frost range covers how to read the range around Washington's dates instead of trusting one.