Pimaco Two climate

Pimaco Two Frost Dates and Growing Season

NOAA 1991-2020 normals for Kartchner Caverns, 15.8 km from Pimaco Two, elevation 4690 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kartchner Caverns. 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 March 20 and the first fall freeze around November 15, a growing season of about 237 days.

Median at 36°F
last April 10, first November 4
Median at 32°F
last March 20, first November 15
Median at 28°F
last February 28, first November 28

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°FApr 28Apr 22Apr 17Apr 12Apr 10Apr 6Apr 3Mar 29Mar 21
32°FApr 11Apr 4Mar 31Mar 25Mar 20Mar 16Mar 10Mar 4Feb 25
28°FMar 21Mar 13Mar 8Mar 3Feb 28Feb 22Feb 16Feb 9Jan 31
24°FMar 3Feb 22Feb 15Feb 10Feb 6Feb 1Jan 26Jan 17Jan 5
20°FFeb 18Feb 8Feb 3Jan 29Jan 22Jan 16Jan 9Jan 3Dec 24
16°FFeb 11Feb 4Jan 31Jan 26Jan 23Jan 17Jan 11Jan 6Jan 3

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°FOct 22Oct 26Oct 30Nov 2Nov 4Nov 7Nov 11Nov 14Nov 18
32°FNov 1Nov 5Nov 9Nov 12Nov 15Nov 18Nov 21Nov 26Dec 2
28°FNov 10Nov 16Nov 19Nov 24Nov 28Dec 1Dec 5Dec 10Dec 19
24°FNov 23Dec 1Dec 5Dec 10Dec 17Dec 23Dec 29Jan 5Jan 19
20°FDec 9Dec 23Dec 31Jan 4Jan 10Jan 15Jan 22Jan 30Feb 6
16°FJan 2Jan 5Jan 10Jan 14Jan 20Jan 24Jan 28Feb 1Feb 7

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°F230221216211207202198192184
32°F265256248242237231225219209
28°F305293285277271265258252241
24°F350336327321313307299289277
20°F365365365365357348337329317
16°F365365365365365365365365352

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
98% of years
20°F or colder
63% of years
16°F or colder
17% 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
2,602
Cooling degree days, base 65°F
1,572
Growing degree days, base 40°F
8,157
Growing degree days, base 45°F
6,467
Growing degree days, base 50°F
4,940
Growing degree days, base 55°F
3,616
Growing degree days, base 60°F
2,500

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January583029
February454067
March3293173
April16619310
May48134551
June0371820
July0412877
August0347812
September4221667
October9062440
November3472152
December581041

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 15.8 km from Pimaco Two. 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 USC00024534 (Kartchner Caverns). Public domain.