Valentine climate

Valentine Frost Dates and Growing Season

NOAA 1991-2020 normals for Valentine #1, 0.3 km from Valentine, elevation 2589 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Valentine #1. 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 6 and the first fall freeze around October 4, a growing season of about 149 days.

Median at 36°F
last May 15, first September 26
Median at 32°F
last May 6, first October 4
Median at 28°F
last April 28, first October 13

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 27May 23May 20May 18May 15May 13May 10May 8May 4
32°FMay 19May 15May 12May 9May 6May 4May 2Apr 29Apr 24
28°FMay 12May 6May 3Apr 30Apr 28Apr 24Apr 21Apr 17Apr 12
24°FMay 3Apr 28Apr 23Apr 20Apr 16Apr 13Apr 10Apr 7Apr 2
20°FApr 24Apr 18Apr 14Apr 10Apr 6Apr 3Mar 31Mar 27Mar 20
16°FApr 14Apr 7Apr 3Mar 31Mar 28Mar 24Mar 20Mar 15Mar 9

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 12Sep 18Sep 21Sep 24Sep 26Sep 28Oct 1Oct 3Oct 7
32°FSep 22Sep 27Sep 30Oct 2Oct 4Oct 6Oct 9Oct 12Oct 16
28°FSep 30Oct 4Oct 8Oct 11Oct 13Oct 16Oct 18Oct 21Oct 25
24°FOct 7Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Oct 30Nov 3
20°FOct 17Oct 23Oct 26Oct 28Oct 31Nov 2Nov 5Nov 9Nov 13
16°FOct 27Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 18Nov 23

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°F149144140137133129125121115
32°F168162157153149146143137131
28°F188181176172167164160155148
24°F206200194191186182177173166
20°F227219215210206201196191184
16°F247240235230225221217210202

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
6,711
Cooling degree days, base 65°F
921
Growing degree days, base 40°F
5,127
Growing degree days, base 45°F
4,021
Growing degree days, base 50°F
3,051
Growing degree days, base 55°F
2,213
Growing degree days, base 60°F
1,504

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26000
February1,06102
March852023
April535285
May25440282
June45169575
July4336796
August12274727
September11896435
October4905115
November866012
December1,21601

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 0.3 km from Valentine. 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 USC00258751 (Valentine #1). Public domain.