Welsh climate

Welsh Frost Dates and Growing Season

NOAA 1991-2020 normals for Jennings, 15.8 km from Welsh, elevation 25 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jennings. 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 February 19 and the first fall freeze around December 4, a growing season of about 292 days.

Median at 36°F
last March 6, first November 19
Median at 32°F
last February 19, first December 4
Median at 28°F
last January 31, first December 28

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°FMar 29Mar 20Mar 15Mar 10Mar 6Mar 2Feb 26Feb 21Feb 12
32°FMar 13Mar 6Mar 1Feb 25Feb 19Feb 13Feb 6Jan 31Jan 21
28°FMar 1Feb 19Feb 10Feb 3Jan 31Jan 26Jan 20Jan 12Dec 30
24°FFeb 18Feb 4Feb 1Jan 28Jan 23Jan 16Jan 11Jan 4Dec 25
20°FFeb 15Feb 2Jan 31Jan 28Jan 19Jan 13Jan 10Jan 6Jan 1
16°F–––––––––

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°FNov 3Nov 7Nov 12Nov 16Nov 19Nov 23Nov 27Dec 1Dec 8
32°FNov 12Nov 19Nov 26Dec 1Dec 4Dec 9Dec 16Dec 25Jan 4
28°FNov 28Dec 4Dec 10Dec 21Dec 28Jan 1Jan 6Jan 11Jan 27
24°FDec 10Dec 27Jan 1Jan 3Jan 8Jan 11Jan 18Jan 28Feb 2
20°FJan 1Jan 2Jan 6Jan 8Jan 12Jan 17Jan 26Feb 1Feb 8
16°F–––––––––

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°F288277270264259252246240230
32°F330317309300292284276268256
28°F365353343336330322313305291
24°F365365365365365360348337326
20°F365365365365365365365365359
16°F365365365365365365365365365

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
99% of years
28°F or colder
89% of years
24°F or colder
50% of years
20°F or colder
14% of years
16°F or colder
2% 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
1,618
Cooling degree days, base 65°F
2,667
Growing degree days, base 40°F
10,211
Growing degree days, base 45°F
8,463
Growing degree days, base 50°F
6,804
Growing degree days, base 55°F
5,272
Growing degree days, base 60°F
3,885

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4478135
February30814178
March17150359
April54128525
May4308769
June0457907
July0525990
August0530995
September1401850
October42183607
November20244314
December38717174

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 15.8 km from Welsh. 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 USC00164700 (Jennings). Public domain.