Hays climate

Hays Frost Dates and Growing Season

NOAA 1991-2020 normals for Hays, 1.6 km from Hays, elevation 1990 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hays. 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 19 and the first fall freeze around October 22, a growing season of about 184 days.

Median at 36°F
last April 30, first October 13
Median at 32°F
last April 19, first October 22
Median at 28°F
last April 9, 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 11May 7May 4May 1Apr 30Apr 27Apr 24Apr 21Apr 17
32°FMay 2Apr 28Apr 24Apr 22Apr 19Apr 17Apr 14Apr 11Apr 7
28°FApr 22Apr 19Apr 15Apr 12Apr 9Apr 6Apr 4Mar 31Mar 24
24°FApr 15Apr 9Apr 5Apr 2Mar 31Mar 26Mar 22Mar 16Mar 10
20°FApr 6Apr 1Mar 27Mar 21Mar 16Mar 12Mar 8Mar 4Feb 28
16°FMar 27Mar 18Mar 12Mar 8Mar 5Mar 2Feb 27Feb 22Feb 16

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 28Oct 3Oct 6Oct 10Oct 13Oct 15Oct 18Oct 21Oct 24
32°FOct 6Oct 12Oct 16Oct 19Oct 22Oct 24Oct 27Oct 31Nov 4
28°FOct 16Oct 21Oct 24Oct 27Oct 31Nov 2Nov 5Nov 7Nov 12
24°FOct 24Oct 29Nov 1Nov 5Nov 7Nov 10Nov 13Nov 17Nov 21
20°FNov 1Nov 5Nov 9Nov 14Nov 17Nov 20Nov 24Nov 27Dec 3
16°FNov 8Nov 16Nov 20Nov 25Nov 28Dec 1Dec 5Dec 11Dec 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°F182176172168165161157152146
32°F202196191187184180175170164
28°F223217212208205200196191183
24°F247239233229225219214208200
20°F269261254249245240235228219
16°F292284278273268262257250241

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
4,935
Cooling degree days, base 65°F
1,546
Growing degree days, base 40°F
6,612
Growing degree days, base 45°F
5,306
Growing degree days, base 50°F
4,158
Growing degree days, base 55°F
3,155
Growing degree days, base 60°F
2,286

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,01701
February831012
March634365
April36213172
May13699439
June7327769
July1470934
August2411874
September50197599
October29727248
November649144
December95003

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 1.6 km from Hays. 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 USC00143523 (Hays). Public domain.