Hart climate

Hart Frost Dates and Growing Season

NOAA 1991-2020 normals for Hart, 1.7 km from Hart, elevation 3663 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hart. 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 22 and the first fall freeze around October 21, a growing season of about 182 days.

Median at 36°F
last April 30, first October 13
Median at 32°F
last April 22, first October 21
Median at 28°F
last April 10, first October 31

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 10May 7May 4May 2Apr 30Apr 29Apr 26Apr 23Apr 19
32°FMay 3Apr 30Apr 27Apr 24Apr 22Apr 19Apr 15Apr 13Apr 8
28°FApr 25Apr 21Apr 17Apr 14Apr 10Apr 7Apr 4Apr 1Mar 26
24°FApr 16Apr 8Apr 4Apr 1Mar 28Mar 24Mar 19Mar 15Mar 9
20°FApr 1Mar 26Mar 21Mar 17Mar 13Mar 9Mar 6Mar 2Feb 25
16°FMar 17Mar 11Mar 7Mar 3Feb 28Feb 25Feb 21Feb 17Feb 10

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°FOct 1Oct 5Oct 8Oct 11Oct 13Oct 15Oct 17Oct 20Oct 24
32°FOct 8Oct 13Oct 16Oct 18Oct 21Oct 24Oct 26Oct 30Nov 2
28°FOct 18Oct 23Oct 26Oct 28Oct 31Nov 2Nov 5Nov 7Nov 12
24°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 11Nov 14Nov 18Nov 23
20°FNov 4Nov 9Nov 12Nov 15Nov 18Nov 22Nov 24Nov 28Dec 3
16°FNov 14Nov 19Nov 23Nov 26Nov 29Dec 1Dec 5Dec 10Dec 17

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°F181175170167164161158152147
32°F201195190186182179175171166
28°F223216211207202198194189182
24°F250241237232227222217212204
20°F272265260255251247241236228
16°F298290283278274269264258250

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
4,415
Cooling degree days, base 65°F
1,117
Growing degree days, base 40°F
6,416
Growing degree days, base 45°F
5,033
Growing degree days, base 50°F
3,816
Growing degree days, base 55°F
2,763
Growing degree days, base 60°F
1,864

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January91003
February720012
March556172
April31110197
May10790453
June6254697
July1333797
August2290753
September50125527
October26915250
November603049
December88005

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 1.7 km from Hart. 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 USC00413972 (Hart). Public domain.