White Rock climate

White Rock Frost Dates and Growing Season

NOAA 1991-2020 normals for Los Alamos, 11.3 km from White Rock, elevation 7424 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Los Alamos. 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 2 and the first fall freeze around October 12, a growing season of about 162 days.

Median at 36°F
last May 16, first October 4
Median at 32°F
last May 2, first October 12
Median at 28°F
last April 20, first October 23

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 31May 25May 22May 18May 16May 13May 10May 5Apr 30
32°FMay 17May 13May 9May 4May 2Apr 30Apr 27Apr 23Apr 19
28°FMay 4May 1Apr 26Apr 23Apr 20Apr 18Apr 14Apr 11Apr 6
24°FApr 23Apr 18Apr 14Apr 9Apr 7Apr 4Apr 1Mar 27Mar 20
20°FApr 8Apr 3Mar 28Mar 24Mar 20Mar 15Mar 11Mar 6Mar 2
16°FMar 22Mar 15Mar 9Mar 6Mar 3Feb 28Feb 23Feb 17Feb 11

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 19Sep 25Sep 28Oct 1Oct 4Oct 6Oct 8Oct 12Oct 17
32°FOct 1Oct 3Oct 6Oct 9Oct 12Oct 15Oct 18Oct 21Oct 25
28°FOct 9Oct 14Oct 17Oct 20Oct 23Oct 25Oct 29Nov 1Nov 6
24°FOct 18Oct 22Oct 26Oct 30Nov 1Nov 5Nov 8Nov 12Nov 17
20°FOct 24Oct 31Nov 3Nov 7Nov 11Nov 14Nov 18Nov 22Nov 26
16°FNov 2Nov 8Nov 14Nov 18Nov 22Nov 24Nov 27Dec 1Dec 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°F160153149144140136132126118
32°F180173169165162158153148141
28°F203196191187182179174169163
24°F230222215210206201197192185
20°F260251245239234228222216208
16°F289279273267262257250244235

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
5,929
Cooling degree days, base 65°F
397
Growing degree days, base 40°F
4,615
Growing degree days, base 45°F
3,452
Growing degree days, base 50°F
2,451
Growing degree days, base 55°F
1,606
Growing degree days, base 60°F
916

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07300
February86701
March729013
April504066
May25615248
June44110516
July9152608
August2293536
September13127351
October4480104
November77608
December1,07100

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 11.3 km from White Rock. 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 USC00295084 (Los Alamos). Public domain.