Buffalo County climate

Buffalo County Frost Dates and Growing Season

NOAA 1991-2020 normals for Gann Valley 3 Nne, 18.5 km from Buffalo County, elevation 1646 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Gann Valley 3 Nne. 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 1, a growing season of about 146 days.

Median at 36°F
last May 16, first September 24
Median at 32°F
last May 7, first October 1
Median at 28°F
last April 30, first October 8

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 30May 26May 22May 19May 16May 13May 10May 7May 3
32°FMay 21May 17May 13May 10May 7May 5May 2Apr 30Apr 25
28°FMay 13May 8May 4May 2Apr 30Apr 27Apr 24Apr 19Apr 14
24°FMay 4Apr 30Apr 28Apr 24Apr 21Apr 18Apr 15Apr 11Apr 6
20°FApr 27Apr 22Apr 18Apr 14Apr 11Apr 8Apr 5Apr 2Mar 26
16°FApr 19Apr 13Apr 9Apr 6Apr 3Mar 31Mar 28Mar 21Mar 14

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 10Sep 16Sep 19Sep 22Sep 24Sep 26Sep 29Oct 1Oct 5
32°FSep 19Sep 24Sep 27Sep 29Oct 1Oct 3Oct 6Oct 9Oct 13
28°FSep 27Sep 30Oct 3Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21
24°FOct 2Oct 6Oct 11Oct 14Oct 16Oct 19Oct 21Oct 25Oct 29
20°FOct 11Oct 16Oct 19Oct 22Oct 25Oct 27Oct 30Nov 3Nov 7
16°FOct 19Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 16

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°F145140136132128125121116110
32°F162156152149146142138133127
28°F181175169166162158155150144
24°F197191186182178174170166158
20°F216209204199195191186182174
16°F234227222217212208203198191

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
7,912
Cooling degree days, base 65°F
745
Growing degree days, base 40°F
4,662
Growing degree days, base 45°F
3,647
Growing degree days, base 50°F
2,752
Growing degree days, base 55°F
1,966
Growing degree days, base 60°F
1,296

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,54500
February1,26201
March1,029113
April622159
May28030258
June54131529
July5283743
August20221666
September15172384
October574692
November98006
December1,39100

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 18.5 km from Buffalo County. 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 USC00393211 (Gann Valley 3 Nne). Public domain.