Diamond Bar, CA 91765 Frost Dates
When can you plant in Diamond Bar, CA?
The last spring frost here typically falls around 01/08, about 133 days from today. The first fall frost typically arrives around 12/28, about 354 frost-free days later.
Diamond Bar sits in USDA Zone 10a (30 to 35°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
About 17 weeks of growing season left in Diamond Bar 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
01/08 is the middle of 30 years of NOAA records, not a promise. Plant by 02/18 and you're betting against frost in roughly 9 years out of 10. 12/14 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Diamond Bar compares
Diamond Bar's growing season runs about 354 days, ranking 2,168 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 972 of 2,555.
Learn more
the frost range covers how to read the range around Diamond Bar's dates instead of trusting one. local microclimates covers what one yard in Diamond Bar can differ from the 91765 normal.