Hillsboro, OR 97124 Frost Dates
When can you plant in Hillsboro, OR?
Around 02/11 is the usual last spring frost, about 167 days away. The first fall frost typically arrives around 12/05, about 303 frost-free days later.
The USDA Plant Hardiness Zone Map puts Hillsboro 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 14 weeks of growing season left in Hillsboro before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 02/11 isn't a guarantee
02/11 is the middle of 30 years of NOAA records, not a promise. Plant by 03/05 and you're betting against frost in roughly 9 years out of 10. 12/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hillsboro compares
At roughly 303 frost-free days, Hillsboro places 3,768 of 40,283 ZIP codes in this dataset. Within OR, it ranks 15 of 463.
Learn more
the frost range covers how to read the range around Hillsboro's dates instead of trusting one. local microclimates covers what one yard in Hillsboro can differ from the 97124 normal.