Webb climate

Webb Frost Dates and Growing Season

NOAA 1991-2020 normals for Headland, 13 km from Webb, elevation 370 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Headland. 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 5 and the first fall freeze around November 24, a growing season of about 264 days.

Median at 36°F
last March 21, first November 11
Median at 32°F
last March 5, first November 24
Median at 28°F
last February 19, first December 9

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 7Apr 3Mar 30Mar 26Mar 21Mar 17Mar 12Mar 7Feb 28
32°FMar 25Mar 19Mar 15Mar 10Mar 5Mar 1Feb 25Feb 19Feb 9
28°FMar 13Mar 6Feb 28Feb 24Feb 19Feb 13Feb 6Jan 31Jan 23
24°FMar 2Feb 21Feb 13Feb 6Feb 1Jan 28Jan 22Jan 14Jan 2
20°FFeb 18Feb 8Feb 1Jan 28Jan 23Jan 18Jan 11Jan 5Dec 28
16°FFeb 11Feb 4Jan 30Jan 25Jan 21Jan 14Jan 8Jan 4Dec 28

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 28Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 23Dec 1
32°FNov 6Nov 12Nov 16Nov 20Nov 24Nov 28Dec 3Dec 8Dec 18
28°FNov 17Nov 24Nov 30Dec 4Dec 9Dec 15Dec 24Jan 1Jan 10
24°FDec 3Dec 10Dec 18Dec 25Jan 1Jan 5Jan 11Jan 19Jan 30
20°FDec 17Dec 27Jan 1Jan 6Jan 10Jan 16Jan 21Jan 27Feb 4
16°FDec 23Jan 1Jan 5Jan 9Jan 14Jan 20Jan 24Jan 31Feb 7

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°F263253247241236230223216209
32°F297284276270264259253246236
28°F334320312305298291282274262
24°F365353343336331323315306298
20°F365365365365357348338332318
16°F365365365365365365365356338

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
99% of years
24°F or colder
88% of years
20°F or colder
57% of years
16°F or colder
23% 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
1,818
Cooling degree days, base 65°F
2,517
Growing degree days, base 40°F
9,877
Growing degree days, base 45°F
8,143
Growing degree days, base 50°F
6,512
Growing degree days, base 55°F
5,021
Growing degree days, base 60°F
3,683

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4905114
February3438149
March20342326
April69107489
May6307766
June0456906
July0533998
August0501966
September1371820
October56146557
November23032276
December4199146

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 13 km from Webb. 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 USC00013761 (Headland). Public domain.