Walsh climate

Walsh Frost Dates and Growing Season

NOAA 1991-2020 normals for Walsh 1 W, 1.9 km from Walsh, elevation 3978 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Walsh 1 W. 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 14, a growing season of about 166 days.

Median at 36°F
last May 9, first October 5
Median at 32°F
last April 30, first October 14
Median at 28°F
last April 19, first October 22

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°FMay 23May 19May 15May 12May 9May 7May 4May 2Apr 29
32°FMay 12May 7May 4May 2Apr 30Apr 28Apr 24Apr 20Apr 17
28°FMay 4Apr 29Apr 25Apr 22Apr 19Apr 17Apr 13Apr 10Apr 5
24°FApr 23Apr 19Apr 15Apr 12Apr 8Apr 6Apr 3Mar 30Mar 23
20°FApr 15Apr 9Apr 5Apr 2Mar 30Mar 26Mar 21Mar 16Mar 9
16°FApr 5Mar 29Mar 24Mar 19Mar 15Mar 11Mar 8Mar 3Feb 26

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 24Sep 27Sep 30Oct 3Oct 5Oct 7Oct 9Oct 12Oct 15
32°FOct 1Oct 5Oct 8Oct 11Oct 14Oct 16Oct 18Oct 21Oct 24
28°FOct 9Oct 14Oct 17Oct 19Oct 22Oct 25Oct 27Oct 29Nov 2
24°FOct 18Oct 22Oct 26Oct 30Nov 1Nov 3Nov 6Nov 9Nov 13
20°FOct 26Nov 1Nov 3Nov 6Nov 9Nov 12Nov 15Nov 18Nov 23
16°FNov 2Nov 6Nov 11Nov 14Nov 17Nov 20Nov 24Nov 28Dec 3

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°F162158154151148144141136131
32°F183177173169166162159154149
28°F201196192189185180176172165
24°F225218213208204200196192184
20°F246239233229225221216211203
16°F272262257252247243237231222

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
5,114
Cooling degree days, base 65°F
1,215
Growing degree days, base 40°F
6,153
Growing degree days, base 45°F
4,867
Growing degree days, base 50°F
3,740
Growing degree days, base 55°F
2,759
Growing degree days, base 60°F
1,919

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,00603
February81909
March650055
April3927155
May15168395
June17256690
July2396859
August5325786
September66147535
October34016209
November680040
December98704

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 1.9 km from Walsh. 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 USC00058793 (Walsh 1 W). Public domain.