Mammoth Lakes climate

Mammoth Lakes Frost Dates and Growing Season

NOAA 1991-2020 normals for Mammoth Lakes RS, 0.9 km from Mammoth Lakes, elevation 7805 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mammoth Lakes RS. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around June 10 and the first fall freeze around September 17, a growing season of about 98 days.

Median at 32°F
last June 10, first September 17
Median at 28°F
last May 31, first October 1

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°F–––––––––
32°FJun 30Jun 23Jun 17Jun 14Jun 10Jun 7Jun 5Jun 1May 29
28°FJun 16Jun 9Jun 6Jun 3May 31May 28May 23May 18May 9
24°FJun 4May 28May 22May 17May 12May 7May 2Apr 29Apr 23
20°FMay 19May 9May 3Apr 29Apr 26Apr 23Apr 19Apr 14Apr 8
16°FApr 30Apr 25Apr 20Apr 16Apr 12Apr 9Apr 5Apr 2Mar 23

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°F–––––––––
32°FSep 2Sep 6Sep 10Sep 14Sep 17Sep 20Sep 23Sep 27Oct 2
28°FSep 15Sep 20Sep 24Sep 28Oct 1Oct 3Oct 6Oct 10Oct 16
24°FSep 27Oct 1Oct 5Oct 8Oct 11Oct 15Oct 19Oct 22Oct 29
20°FOct 7Oct 11Oct 15Oct 21Oct 24Oct 29Nov 1Nov 5Nov 10
16°FOct 16Oct 22Oct 28Nov 1Nov 4Nov 7Nov 12Nov 16Nov 23

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F948782787368635644
32°F1201121071029893898475
28°F15014013412912411911410799
24°F179169163158152147142134124
20°F206196189184180174169163153
16°F233223216211206200195189178

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
7,722
Cooling degree days, base 65°F
65
Growing degree days, base 40°F
3,032
Growing degree days, base 45°F
2,081
Growing degree days, base 50°F
1,322
Growing degree days, base 55°F
721
Growing degree days, base 60°F
291

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11900
February99800
March96600
April77506
May544064
June2685216
July8634415
August10423385
September2862197
October606036
November86303
December1,10800

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 0.9 km from Mammoth Lakes. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00045280 (Mammoth Lakes RS). Public domain.