Doolittle climate

Doolittle Frost Dates and Growing Season

NOAA 1991-2020 normals for Rolla Missouri S&t, 9.4 km from Doolittle, elevation 1173 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rolla Missouri S&t. 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 5 and the first fall freeze around November 1, a growing season of about 207 days.

Median at 36°F
last April 18, first October 21
Median at 32°F
last April 5, first November 1
Median at 28°F
last March 26, first November 10

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 2Apr 27Apr 23Apr 21Apr 18Apr 14Apr 10Apr 6Apr 1
32°FApr 22Apr 16Apr 11Apr 8Apr 5Apr 2Mar 31Mar 26Mar 21
28°FApr 10Apr 5Apr 1Mar 30Mar 26Mar 23Mar 20Mar 16Mar 10
24°FApr 1Mar 28Mar 23Mar 20Mar 17Mar 14Mar 10Mar 5Feb 28
20°FMar 24Mar 18Mar 15Mar 11Mar 7Mar 4Mar 1Feb 26Feb 19
16°FMar 17Mar 11Mar 6Mar 3Feb 28Feb 25Feb 20Feb 13Feb 6

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°FOct 7Oct 12Oct 16Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1
32°FOct 18Oct 22Oct 26Oct 30Nov 1Nov 3Nov 5Nov 9Nov 15
28°FOct 28Nov 1Nov 4Nov 6Nov 10Nov 13Nov 17Nov 23Nov 28
24°FNov 4Nov 9Nov 13Nov 17Nov 21Nov 25Nov 29Dec 2Dec 7
20°FNov 13Nov 19Nov 23Nov 27Dec 1Dec 4Dec 8Dec 12Dec 19
16°FNov 23Nov 29Dec 3Dec 7Dec 11Dec 15Dec 21Dec 24Jan 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°F205199194190186182178173166
32°F231222216212207203199195188
28°F252244239233229224220215207
24°F273264259253249244239234225
20°F294284278272267262257250243
16°F315305298292287282276268259

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
4,612
Cooling degree days, base 65°F
1,487
Growing degree days, base 40°F
6,847
Growing degree days, base 45°F
5,502
Growing degree days, base 50°F
4,294
Growing degree days, base 55°F
3,226
Growing degree days, base 60°F
2,288

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03408
February808019
March613581
April29130242
May92116492
June8288730
July0428893
August1392855
September44183590
October25141289
November572479
December899016

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 9.4 km from Doolittle. 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 USC00237263 (Rolla Missouri S&t). Public domain.