El Mirage, AZ 85379 Frost Dates
When can you plant in El Mirage, AZ?
Around 01/20 is the usual last spring frost, about 145 days away. The first fall frost typically arrives around 12/15, about 331 frost-free days later.
The USDA Plant Hardiness Zone Map puts El Mirage in Zone 9b (25 to 30°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 16 weeks of growing season left in El Mirage before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 01/20 isn't a guarantee
01/20 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. 12/23 is the safer bet, historically only a 1-in-10 chance of frost that late.
How El Mirage compares
El Mirage's growing season runs about 331 days, ranking 2,928 of 40,283 US ZIP codes measured here, longest to shortest. Within AZ, it ranks 175 of 506.
Learn more
the frost range covers how to read the range around El Mirage's dates instead of trusting one. local microclimates covers what one yard in El Mirage can differ from the 85379 normal.