Sisters, OR 97730 Frost Dates
Frost dates for Sisters, OR, ZIP 97730
Typically, the last spring freeze lands around 05/05, roughly 250 days out. The first fall frost typically arrives around 10/07, about 154 frost-free days later.
Sisters sits in USDA Zone 6b (-5 to 0°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
Zone 6b around Sisters has about 6 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
05/05 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/29 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Sisters compares
Sisters's growing season runs about 154 days, ranking 34,321 of 40,283 US ZIP codes measured here, longest to shortest. Within OR, it ranks 346 of 463.
Learn more
the frost range explains how to read the range around Sisters's dates instead of trusting one, and local microclimates explains what one yard in Sisters can differ from the 97730 normal.