Tonopah climate

Tonopah Frost Dates and Growing Season

NOAA 1991-2020 normals for Tonopah, 0.6 km from Tonopah, elevation 6010 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tonopah. 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 April 30 and the first fall freeze around October 22, a growing season of about 173 days.

Median at 36°F
last May 15, first October 12
Median at 32°F
last April 30, first October 22
Median at 28°F
last April 16, first November 4

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 28May 23May 18May 15May 11May 6May 2Apr 27
32°FMay 22May 14May 8May 3Apr 30Apr 27Apr 23Apr 20Apr 14
28°FMay 7Apr 30Apr 24Apr 20Apr 16Apr 12Apr 8Apr 3Mar 26
24°FApr 18Apr 12Apr 7Apr 2Mar 28Mar 21Mar 15Mar 10Mar 2
20°FApr 5Mar 24Mar 15Mar 10Mar 5Mar 1Feb 27Feb 21Feb 14
16°FMar 9Mar 3Feb 28Feb 23Feb 17Feb 13Feb 6Jan 29Jan 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 28Oct 2Oct 6Oct 9Oct 12Oct 15Oct 18Oct 22Oct 28
32°FOct 5Oct 11Oct 14Oct 19Oct 22Oct 26Oct 29Nov 3Nov 8
28°FOct 16Oct 22Oct 27Nov 1Nov 4Nov 7Nov 10Nov 14Nov 19
24°FOct 27Nov 3Nov 7Nov 11Nov 15Nov 19Nov 23Nov 27Dec 2
20°FNov 7Nov 13Nov 19Nov 24Nov 27Dec 1Dec 4Dec 8Dec 13
16°FNov 18Nov 26Dec 1Dec 5Dec 8Dec 12Dec 15Dec 20Dec 27

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°F172164159153149145140134126
32°F198190183178173169163156146
28°F226218211205201195189182172
24°F263253245239233226219211201
20°F296285277270265258252243230
16°F333319309302295287281274265

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
5,755
Cooling degree days, base 65°F
796
Growing degree days, base 40°F
5,097
Growing degree days, base 45°F
3,917
Growing degree days, base 50°F
2,916
Growing degree days, base 55°F
2,079
Growing degree days, base 60°F
1,381

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,01700
February84701
March732011
April540053
May28117233
June56137532
July2302765
August2248711
September8288464
October4084132
November741015
December1,04900

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 0.6 km from Tonopah. 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 USC00268160 (Tonopah). Public domain.