Mammoth Lakes, CA 93546 Frost Dates
93546, near Mammoth Lakes, CA: the frost window
Typically, the last spring freeze lands around 06/10, roughly 286 days out. Fall's first freeze usually shows up around 09/17, roughly 98 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Mammoth Lakes in Zone 6a (-10 to -5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Mammoth Lakes's growing season runs out in roughly 3 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
06/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/30 and only about 1 year in 10 sees frost after that.
Mammoth Lakes against the rest of the dataset
Mammoth Lakes's growing season runs about 98 days, ranking 39,753 of 40,283 US ZIP codes measured here, longest to shortest. Within CA, it ranks 2,525 of 2,555.
Learn more
Two guides worth reading on 93546: local microclimates, on what one yard in Mammoth Lakes can differ from the 93546 normal, and zone vs. frost date, on why Zone 6a and Mammoth Lakes's frost date answer different questions.