Monroe, OR 97456 Frost Dates
When can you plant in Monroe, OR?
Typically, the last spring freeze lands around 04/11, roughly 226 days out. The first fall frost typically arrives around 10/30, about 203 frost-free days later.
The USDA Plant Hardiness Zone Map puts Monroe 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 9 weeks of growing season left in Monroe before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/11 isn't a guarantee
04/11 is the middle of 30 years of NOAA records, not a promise. Plant by 03/11 and you're betting against frost in roughly 9 years out of 10. 05/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Monroe compares
Monroe's growing season runs about 203 days, ranking 17,009 of 40,283 US ZIP codes measured here, longest to shortest. Within OR, it ranks 222 of 463.
Learn more
zone vs. frost date covers why Zone 8b and Monroe's frost date answer different questions. the frost range covers how to read the range around Monroe's dates instead of trusting one.