Lemmon climate

Lemmon Frost Dates and Growing Season

NOAA 1991-2020 normals for Lemmon, 0.2 km from Lemmon, elevation 2567 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lemmon. 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 May 10 and the first fall freeze around September 30, a growing season of about 142 days.

Median at 36°F
last May 20, first September 22
Median at 32°F
last May 10, first September 30
Median at 28°F
last May 1, first October 9

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°FJun 2May 30May 26May 23May 20May 17May 14May 12May 8
32°FMay 24May 19May 15May 13May 10May 8May 6May 3Apr 30
28°FMay 14May 9May 6May 4May 1Apr 29Apr 26Apr 21Apr 17
24°FMay 3Apr 30Apr 26Apr 23Apr 20Apr 17Apr 14Apr 11Apr 6
20°FApr 25Apr 19Apr 16Apr 13Apr 10Apr 8Apr 5Apr 2Mar 28
16°FApr 15Apr 10Apr 7Apr 5Apr 2Mar 31Mar 28Mar 23Mar 15

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°FSep 9Sep 15Sep 18Sep 20Sep 22Sep 25Sep 27Sep 30Oct 3
32°FSep 18Sep 22Sep 25Sep 28Sep 30Oct 2Oct 5Oct 8Oct 12
28°FSep 25Sep 30Oct 3Oct 6Oct 9Oct 12Oct 14Oct 18Oct 22
24°FOct 2Oct 7Oct 12Oct 15Oct 18Oct 21Oct 24Oct 27Nov 1
20°FOct 13Oct 17Oct 21Oct 24Oct 27Oct 30Nov 2Nov 5Nov 10
16°FOct 21Oct 26Oct 30Nov 1Nov 4Nov 7Nov 10Nov 14Nov 21

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°F141135130126122119116112106
32°F159153149145142139135131125
28°F178173168164160156152148142
24°F199193188184180177172168161
20°F220212206202198194189185179
16°F237230224218214210206201193

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
7,638
Cooling degree days, base 65°F
651
Growing degree days, base 40°F
4,547
Growing degree days, base 45°F
3,515
Growing degree days, base 50°F
2,608
Growing degree days, base 55°F
1,828
Growing degree days, base 60°F
1,172

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,43100
February1,19601
March989010
April610154
May29718228
June7294474
July13250702
August22217661
September15567375
October556595
November96909
December1,33000

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 0.2 km from Lemmon. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00394864 (Lemmon). Public domain.