Blanco climate

Blanco Frost Dates and Growing Season

NOAA 1991-2020 normals for Blanco, 0.7 km from Blanco, elevation 1310 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Blanco. 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 20 and the first fall freeze around November 10, a growing season of about 236 days.

Median at 36°F
last April 3, first November 1
Median at 32°F
last March 20, first November 10
Median at 28°F
last March 6, first November 23

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 24Apr 17Apr 11Apr 6Apr 3Mar 31Mar 27Mar 22Mar 14
32°FApr 8Apr 2Mar 30Mar 25Mar 20Mar 16Mar 11Mar 5Feb 28
28°FMar 28Mar 19Mar 14Mar 10Mar 6Mar 3Feb 27Feb 20Feb 8
24°FMar 16Mar 7Mar 3Feb 28Feb 21Feb 14Feb 4Jan 28Jan 17
20°FMar 5Feb 27Feb 17Feb 5Jan 31Jan 22Jan 15Jan 3Dec 20
16°FFeb 28Feb 10Jan 31Jan 22Jan 16Jan 9Jan 6Dec 30Dec 16

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 27Oct 30Nov 1Nov 3Nov 6Nov 10Nov 16
32°FOct 27Nov 1Nov 3Nov 6Nov 10Nov 14Nov 19Nov 25Dec 2
28°FNov 3Nov 9Nov 13Nov 18Nov 23Nov 28Dec 2Dec 7Dec 16
24°FNov 15Nov 22Nov 28Dec 2Dec 8Dec 13Dec 20Dec 28Jan 7
20°FNov 28Dec 6Dec 13Dec 21Dec 29Jan 2Jan 9Jan 21Feb 10
16°FDec 13Dec 21Dec 30Jan 3Jan 7Jan 12Jan 19Feb 1Feb 19

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°F237228223217213208203196188
32°F263253247242236230224218209
28°F296283275269262256250243235
24°F335321311303296288279272261
20°F365365355343334326314303291
16°F365365365365365365359347330

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
82% of years
16°F or colder
38% 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
2,145
Cooling degree days, base 65°F
2,351
Growing degree days, base 40°F
9,409
Growing degree days, base 45°F
7,716
Growing degree days, base 50°F
6,141
Growing degree days, base 55°F
4,714
Growing degree days, base 60°F
3,445

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January545278
February3927124
March24431286
April9292454
May14248699
June0422871
July0519984
August0527992
September5335780
October80137527
November28126242
December4924106

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 0.7 km from Blanco. 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 USC00410832 (Blanco). Public domain.