Monmouth, OR 97361 Frost Dates
When can you plant in Monmouth, OR?
Around 04/18 is the usual last spring frost, about 233 days away. The first fall frost typically arrives around 11/07, about 202 frost-free days later.
The USDA Plant Hardiness Zone Map puts Monmouth in Zone 8b (15 to 20°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
About 10 weeks of growing season left in Monmouth before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Monmouth's last frost
04/18 is the middle of 30 years of NOAA records, not a promise. Plant by 03/27 and you're betting against frost in roughly 9 years out of 10. 05/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Monmouth compares
About 202 days separate Monmouth's last and first frost, putting it 17,194 of 40,283 ZIP codes nationally. Within OR, it ranks 223 of 463.
Learn more
the frost range covers how to read the range around Monmouth's dates instead of trusting one. local microclimates covers what one yard in Monmouth can differ from the 97361 normal.