Walker climate

Walker Frost Dates and Growing Season

NOAA 1991-2020 normals for Walker, 1.3 km from Walker, elevation 1430 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Walker. 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 4 and the first fall freeze around October 7, a growing season of about 155 days.

Median at 36°F
last May 14, first September 28
Median at 32°F
last May 4, first October 7
Median at 28°F
last April 25, first October 19

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 30May 25May 21May 17May 14May 11May 8May 4May 1
32°FMay 20May 14May 10May 7May 4May 2Apr 30Apr 26Apr 21
28°FMay 8May 2Apr 30Apr 28Apr 25Apr 22Apr 18Apr 15Apr 11
24°FApr 29Apr 23Apr 20Apr 17Apr 15Apr 13Apr 11Apr 7Apr 4
20°FApr 21Apr 17Apr 14Apr 11Apr 9Apr 6Apr 4Apr 2Mar 26
16°FApr 15Apr 11Apr 8Apr 5Apr 3Apr 1Mar 29Mar 23Mar 18

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 13Sep 19Sep 22Sep 25Sep 28Sep 30Oct 2Oct 5Oct 10
32°FSep 23Sep 28Oct 1Oct 4Oct 7Oct 10Oct 14Oct 17Oct 21
28°FOct 3Oct 8Oct 12Oct 15Oct 19Oct 21Oct 25Oct 28Nov 1
24°FOct 14Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 11
20°FOct 26Oct 30Nov 1Nov 4Nov 6Nov 8Nov 10Nov 14Nov 20
16°FOct 31Nov 4Nov 7Nov 9Nov 12Nov 14Nov 17Nov 21Nov 25

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°F153147143139135131127121113
32°F173167163159155151148143136
28°F194188184179176172167163155
24°F213207203199195192188183177
20°F227222217213210206203198191
16°F242236231226223218215211204

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
8,875
Cooling degree days, base 65°F
381
Growing degree days, base 40°F
3,905
Growing degree days, base 45°F
2,964
Growing degree days, base 50°F
2,129
Growing degree days, base 55°F
1,406
Growing degree days, base 60°F
816

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,70500
February1,40600
March1,15602
April707135
May32218209
June8977439
July25151590
August45107527
September22526270
October627153
November1,06504
December1,50300

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 1.3 km from Walker. 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 USC00218618 (Walker). Public domain.