Boonville climate

Boonville Frost Dates and Growing Season

NOAA 1991-2020 normals for Boonville 4 Ssw, 5.9 km from Boonville, elevation 1550 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Boonville 4 Ssw. 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 10 and the first fall freeze around October 4, a growing season of about 145 days.

Median at 36°F
last May 24, first September 25
Median at 32°F
last May 10, first October 4
Median at 28°F
last April 30, first October 15

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°FJun 8Jun 3May 31May 28May 24May 21May 17May 13May 8
32°FMay 28May 22May 18May 14May 10May 7May 4May 1Apr 28
28°FMay 16May 10May 6May 2Apr 30Apr 28Apr 25Apr 22Apr 17
24°FMay 4Apr 30Apr 26Apr 22Apr 20Apr 17Apr 14Apr 10Apr 6
20°FApr 22Apr 19Apr 16Apr 12Apr 9Apr 7Apr 5Apr 2Mar 30
16°FApr 16Apr 11Apr 7Apr 5Apr 3Apr 1Mar 30Mar 25Mar 20

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 12Sep 17Sep 20Sep 23Sep 25Sep 28Sep 30Oct 3Oct 6
32°FSep 22Sep 27Sep 29Oct 1Oct 4Oct 6Oct 9Oct 13Oct 18
28°FOct 1Oct 5Oct 9Oct 12Oct 15Oct 19Oct 22Oct 26Oct 31
24°FOct 10Oct 16Oct 22Oct 25Oct 28Nov 1Nov 3Nov 6Nov 10
20°FOct 25Oct 31Nov 2Nov 4Nov 7Nov 10Nov 13Nov 16Nov 21
16°FNov 3Nov 8Nov 11Nov 14Nov 17Nov 19Nov 22Nov 26Dec 1

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°F143136131126123120115110103
32°F165158153149145142137133126
28°F187180175172167163159154148
24°F209202197192187183179174168
20°F229223217213210206202197189
16°F246240235231228224220216209

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
8,531
Cooling degree days, base 65°F
194
Growing degree days, base 40°F
3,505
Growing degree days, base 45°F
2,571
Growing degree days, base 50°F
1,759
Growing degree days, base 55°F
1,074
Growing degree days, base 60°F
538

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,50700
February1,30900
March1,19204
April755129
May38810159
June14835342
July5673482
August7558448
September25117238
October611152
November94105
December1,29900

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 5.9 km from Boonville. 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 USC00300785 (Boonville 4 Ssw). Public domain.