Chase County climate

Chase County Frost Dates and Growing Season

NOAA 1991-2020 normals for Imperial, 4.3 km from Chase County, elevation 3294 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Imperial. 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 7 and the first fall freeze around October 5, a growing season of about 150 days.

Median at 36°F
last May 15, first September 26
Median at 32°F
last May 7, first October 5
Median at 28°F
last April 29, 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 29May 24May 21May 17May 15May 13May 11May 8May 5
32°FMay 18May 14May 11May 9May 7May 5May 3May 1Apr 27
28°FMay 9May 5May 3May 1Apr 29Apr 26Apr 24Apr 20Apr 16
24°FMay 1Apr 28Apr 25Apr 22Apr 19Apr 16Apr 14Apr 9Apr 3
20°FApr 23Apr 18Apr 14Apr 11Apr 7Apr 4Apr 1Mar 28Mar 23
16°FApr 15Apr 9Apr 5Apr 2Mar 31Mar 26Mar 22Mar 16Mar 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°FSep 14Sep 18Sep 22Sep 24Sep 26Sep 28Oct 1Oct 3Oct 6
32°FSep 24Sep 28Oct 1Oct 3Oct 5Oct 7Oct 9Oct 12Oct 15
28°FOct 1Oct 5Oct 8Oct 11Oct 13Oct 15Oct 18Oct 20Oct 23
24°FOct 10Oct 14Oct 17Oct 19Oct 22Oct 24Oct 26Oct 28Nov 1
20°FOct 16Oct 20Oct 24Oct 26Oct 29Oct 31Nov 3Nov 6Nov 11
16°FOct 22Oct 27Oct 31Nov 3Nov 6Nov 9Nov 12Nov 16Nov 21

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°F148144140136133130127122115
32°F165161157153150147143138133
28°F183178174171167164161157151
24°F203198193189185182178174168
20°F224217213207202199196191183
16°F245237231225221217211206200

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
6,305
Cooling degree days, base 65°F
894
Growing degree days, base 40°F
5,193
Growing degree days, base 45°F
4,056
Growing degree days, base 50°F
3,064
Growing degree days, base 55°F
2,212
Growing degree days, base 60°F
1,493

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17000
February98803
March795023
April527280
May23937293
June35176592
July3327789
August10258713
September11591434
October4644125
November822013
December1,13700

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 4.3 km from Chase County. 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 USC00254110 (Imperial). Public domain.