Cairo climate

Cairo Frost Dates and Growing Season

NOAA 1991-2020 normals for Grand Island AP, 25.1 km from Cairo, elevation 1840 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Grand Island AP. 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 23 and the first fall freeze around October 15, a growing season of about 174 days.

Median at 36°F
last May 3, first October 5
Median at 32°F
last April 23, first October 15
Median at 28°F
last April 12, 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 15May 11May 8May 5May 3Apr 30Apr 28Apr 25Apr 21
32°FMay 6May 2Apr 29Apr 26Apr 23Apr 20Apr 17Apr 14Apr 9
28°FApr 27Apr 22Apr 19Apr 15Apr 12Apr 9Apr 6Apr 4Mar 31
24°FApr 18Apr 12Apr 8Apr 5Apr 3Mar 31Mar 28Mar 24Mar 18
20°FApr 8Apr 3Mar 31Mar 28Mar 25Mar 21Mar 16Mar 13Mar 7
16°FApr 1Mar 27Mar 22Mar 17Mar 13Mar 10Mar 6Mar 2Feb 26

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 22Sep 27Sep 30Oct 2Oct 5Oct 8Oct 11Oct 14Oct 18
32°FSep 29Oct 4Oct 8Oct 12Oct 15Oct 18Oct 20Oct 23Oct 27
28°FOct 9Oct 15Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 5
24°FOct 18Oct 23Oct 27Oct 30Nov 1Nov 4Nov 6Nov 10Nov 16
20°FOct 27Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 20Nov 25
16°FNov 1Nov 7Nov 11Nov 15Nov 18Nov 21Nov 24Nov 29Dec 5

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°F172166162159155152148143137
32°F194187182178174171167162154
28°F211205201197193190185180173
24°F233225220216212207203198191
20°F251244238234230225221216208
16°F272263258253247243238232223

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
5,923
Cooling degree days, base 65°F
1,153
Growing degree days, base 40°F
5,798
Growing degree days, base 45°F
4,606
Growing degree days, base 50°F
3,550
Growing degree days, base 55°F
2,622
Growing degree days, base 60°F
1,825

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21400
February98704
March754141
April43110133
May16772381
June17249682
July1372835
August4304764
September83131501
October38415180
November762028
December1,11901

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 25.1 km from Cairo. 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 USW00014935 (Grand Island AP). Public domain.