Lorena climate

Lorena Frost Dates and Growing Season

NOAA 1991-2020 normals for Mcgregor, 18.4 km from Lorena, elevation 723 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mcgregor. 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 15 and the first fall freeze around November 18, a growing season of about 249 days.

Median at 36°F
last March 29, first November 8
Median at 32°F
last March 15, first November 18
Median at 28°F
last March 2, first December 1

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 18Apr 9Apr 5Apr 1Mar 29Mar 25Mar 20Mar 15Mar 8
32°FApr 4Mar 29Mar 23Mar 18Mar 15Mar 10Mar 5Mar 1Feb 23
28°FMar 21Mar 15Mar 10Mar 5Mar 2Feb 28Feb 21Feb 14Feb 5
24°FMar 10Mar 4Feb 28Feb 21Feb 13Feb 7Jan 31Jan 26Jan 14
20°FMar 3Feb 22Feb 11Feb 4Jan 31Jan 24Jan 15Jan 5Dec 26
16°FFeb 25Feb 10Feb 4Jan 29Jan 21Jan 13Jan 5Dec 31Dec 22

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 23Oct 29Nov 2Nov 5Nov 8Nov 11Nov 15Nov 18Nov 24
32°FNov 2Nov 7Nov 11Nov 15Nov 18Nov 22Nov 25Nov 30Dec 4
28°FNov 11Nov 17Nov 23Nov 27Dec 1Dec 4Dec 7Dec 13Dec 22
24°FNov 25Dec 1Dec 5Dec 10Dec 15Dec 21Dec 27Jan 3Jan 13
20°FDec 4Dec 12Dec 20Dec 26Jan 1Jan 5Jan 12Jan 22Feb 5
16°FDec 12Dec 22Dec 29Jan 3Jan 10Jan 18Jan 25Feb 2Feb 12

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°F251242235230225220215208200
32°F277268262255249244239232222
28°F307296289282275269263256246
24°F342331321312305298292283270
20°F365365355346339331321310300
16°F365365365365365365358348334

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
98% of years
20°F or colder
81% of years
16°F or colder
40% 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
2,289
Cooling degree days, base 65°F
2,474
Growing degree days, base 40°F
9,418
Growing degree days, base 45°F
7,742
Growing degree days, base 50°F
6,185
Growing degree days, base 55°F
4,784
Growing degree days, base 60°F
3,545

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January585163
February4255105
March27822251
April9969424
May14237688
June0450900
July05671,032
August05841,049
September4375820
October68141541
November28621229
December530382

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 18.4 km from Lorena. 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 USC00415757 (Mcgregor). Public domain.