Collierville climate

Collierville Frost Dates and Growing Season

NOAA 1991-2020 normals for Collierville, 4 km from Collierville, elevation 300 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Collierville. 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 29 and the first fall freeze around November 3, a growing season of about 220 days.

Median at 36°F
last April 9, first October 25
Median at 32°F
last March 29, first November 3
Median at 28°F
last March 13, first November 14

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 26Apr 20Apr 16Apr 12Apr 9Apr 6Apr 4Mar 30Mar 24
32°FApr 15Apr 7Apr 4Apr 1Mar 29Mar 24Mar 21Mar 15Mar 9
28°FApr 3Mar 27Mar 21Mar 16Mar 13Mar 9Mar 6Mar 1Feb 24
24°FMar 19Mar 13Mar 8Mar 5Mar 1Feb 27Feb 23Feb 16Feb 6
20°FMar 11Mar 4Feb 28Feb 24Feb 18Feb 12Feb 4Jan 31Jan 19
16°FMar 1Feb 23Feb 15Feb 8Feb 2Jan 30Jan 24Jan 14Jan 4

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 12Oct 17Oct 20Oct 22Oct 25Oct 28Oct 30Nov 2Nov 6
32°FOct 22Oct 26Oct 30Nov 1Nov 3Nov 5Nov 8Nov 13Nov 20
28°FOct 31Nov 3Nov 6Nov 10Nov 14Nov 17Nov 22Nov 28Dec 4
24°FNov 7Nov 13Nov 17Nov 23Nov 29Dec 2Dec 6Dec 14Dec 24
20°FNov 17Nov 28Dec 4Dec 10Dec 18Dec 25Dec 31Jan 4Jan 14
16°FDec 5Dec 15Dec 25Dec 30Jan 2Jan 6Jan 12Jan 20Feb 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°F219213206202198194189184176
32°F246238231226220216211205197
28°F273263256251246240235228219
24°F302292284277272268259252244
20°F336325316308302295288278268
16°F365357346337331324316307297

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
98% of years
16°F or colder
88% 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
3,293
Cooling degree days, base 65°F
1,899
Growing degree days, base 40°F
8,050
Growing degree days, base 45°F
6,527
Growing degree days, base 50°F
5,146
Growing degree days, base 55°F
3,909
Growing degree days, base 60°F
2,830

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January789132
February602150
March41111161
April17557348
May32193626
June1374823
July0491956
August0450914
September15250685
October16264380
November4276126
December678146

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 4 km from Collierville. 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 USC00401950 (Collierville). Public domain.