Loa climate

Loa Frost Dates and Growing Season

NOAA 1991-2020 normals for Loa, 0.3 km from Loa, elevation 7070 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Loa. 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 31 and the first fall freeze around September 21, a growing season of about 112 days.

Median at 36°F
last June 12, first September 12
Median at 32°F
last May 31, first September 21
Median at 28°F
last May 18, first September 29

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 24Jun 21Jun 17Jun 14Jun 12Jun 9Jun 7Jun 4Jun 1
32°FJun 14Jun 9Jun 5Jun 3May 31May 29May 25May 20May 15
28°FJun 3May 30May 25May 20May 18May 13May 9May 5May 1
24°FMay 21May 16May 11May 7May 3May 1Apr 29Apr 24Apr 19
20°FMay 9May 2Apr 29Apr 25Apr 22Apr 18Apr 15Apr 11Apr 6
16°FApr 24Apr 19Apr 15Apr 11Apr 6Apr 3Mar 31Mar 24Mar 16

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°FAug 31Sep 4Sep 6Sep 9Sep 12Sep 14Sep 16Sep 19Sep 22
32°FSep 8Sep 13Sep 16Sep 18Sep 21Sep 23Sep 25Sep 28Oct 1
28°FSep 18Sep 22Sep 24Sep 27Sep 29Oct 1Oct 4Oct 6Oct 11
24°FSep 26Sep 29Oct 2Oct 5Oct 8Oct 11Oct 14Oct 17Oct 23
20°FOct 5Oct 8Oct 13Oct 16Oct 19Oct 22Oct 25Oct 29Nov 2
16°FOct 14Oct 19Oct 23Oct 26Oct 29Nov 1Nov 5Nov 9Nov 13

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°F10610198949087847972
32°F13012411911511210810410093
28°F152146142138134130126120113
24°F177169164160155151147141134
20°F201193188183179175170165157
16°F231219215209205200195189180

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
7,604
Cooling degree days, base 65°F
152
Growing degree days, base 40°F
3,456
Growing degree days, base 45°F
2,482
Growing degree days, base 50°F
1,670
Growing degree days, base 55°F
1,006
Growing degree days, base 60°F
492

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,25400
February1,03200
March90501
April687013
May4331110
June15621321
July2784522
August5042457
September2513219
October622026
November93201
December1,25500

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 0.3 km from Loa. 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 USC00425148 (Loa). Public domain.