Saint Jo climate

Saint Jo Frost Dates and Growing Season

NOAA 1991-2020 normals for Bonita 7NW, 23.9 km from Saint Jo, elevation 980 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bonita 7NW. 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 March 24 and the first fall freeze around November 8, a growing season of about 229 days.

Median at 36°F
last April 4, first November 1
Median at 32°F
last March 24, first November 8
Median at 28°F
last March 11, first November 20

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°FApr 25Apr 19Apr 13Apr 8Apr 4Apr 1Mar 28Mar 24Mar 17
32°FApr 13Apr 4Mar 31Mar 28Mar 24Mar 19Mar 15Mar 11Mar 5
28°FMar 31Mar 24Mar 19Mar 15Mar 11Mar 8Mar 5Feb 28Feb 22
24°FMar 19Mar 13Mar 9Mar 5Mar 2Feb 26Feb 22Feb 16Feb 5
20°FMar 9Mar 3Feb 28Feb 23Feb 15Feb 10Feb 4Jan 28Jan 20
16°FMar 2Feb 23Feb 13Feb 7Feb 1Jan 27Jan 20Jan 12Dec 31

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 18Oct 22Oct 26Oct 29Nov 1Nov 3Nov 6Nov 10Nov 16
32°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 12Nov 15Nov 20Nov 27
28°FNov 1Nov 7Nov 11Nov 17Nov 20Nov 25Nov 29Dec 2Dec 8
24°FNov 11Nov 19Nov 25Nov 29Dec 2Dec 6Dec 11Dec 16Dec 25
20°FNov 25Dec 1Dec 6Dec 12Dec 18Dec 23Dec 30Jan 4Jan 13
16°FDec 5Dec 12Dec 19Dec 25Jan 1Jan 5Jan 11Jan 18Feb 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°F232224217213208203197192185
32°F256246240234229225219213202
28°F280271264259253248242234223
24°F307297289282277272264258246
20°F340329319312306299293282272
16°F365363353343335329321310300

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
99% of years
16°F or colder
85% 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
2,853
Cooling degree days, base 65°F
2,420
Growing degree days, base 40°F
8,944
Growing degree days, base 45°F
7,362
Growing degree days, base 50°F
5,904
Growing degree days, base 55°F
4,589
Growing degree days, base 60°F
3,426

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January700143
February523589
March33822219
April13581408
May31221655
June0441891
July05951,060
August05841,049
September7345787
October120111465
November36213180
December636258

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 23.9 km from Saint Jo. 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 USC00410926 (Bonita 7NW). Public domain.