Frost Dates for 93546 — Mammoth Lakes, California

Half of springs at Mammoth Lakes Rs, CA see their last 32°F night by June 10; only one in ten is past it by May 29, and one in ten still has one after June 30. Planting tender crops after June 17 leaves a 30% risk of a frost on them, after June 23 20%, and after June 30 10%. The 20 days between the even-odds date and the one-in-ten date is narrower than at 88% of the 220 California stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 17 in half of years, as early as September 2 one year in ten, and holds off past October 2 one year in ten. A hard freeze of 28°F follows 14 days later, around October 1; in spring the one-in-ten date for 28°F is June 16, 14 days before the 32°F one. The freeze-free season lasts 98 days in a typical year, shorter than at 99% of the 219 California stations; it reaches 120 days one year in ten and falls short of 75 one year in ten. On average 210 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between November 4 and April 12.

July is the warmest month at Mammoth Lakes Rs, CA, averaging 78°F by day and 49°F at night; January is the coldest at 41°F and 17°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 81% of years.

Warmth for growing adds up to 1,322 growing degree days a year (base 50°F), fewer than at 99% of the 283 California stations. 22% of them (286) have built up by the end of June, and July adds the most, 415.

The nearest other station, Bishop Airport, CA, 33 miles southeast of Mammoth Lakes and 3,702 feet lower, has a last frost 42 days earlier (April 29), a first frost 28 days later (October 15), a season 68 days longer.

The first measurable snow (0.1 inch or more) in Mammoth Lakes usually arrives around October 29, and the last of the season around May 11. Those are the middle dates across the winters of 1991–2020 at Mammoth Lakes Rs, CA, 5.7 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 30 days after the last snow.

ZIP 93546 is 6 miles from Mammoth Lakes Rs, CA, which stands at 7,804 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 93546 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.