Prosperity climate

Prosperity Frost Dates and Growing Season

NOAA 1991-2020 normals for Little Mtn, 11 km from Prosperity, elevation 711 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Little Mtn. 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 22 and the first fall freeze around November 11, a growing season of about 234 days.

Median at 36°F
last April 3, first November 1
Median at 32°F
last March 22, first November 11
Median at 28°F
last March 10, first November 26

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 17Apr 13Apr 9Apr 5Apr 3Mar 31Mar 28Mar 24Mar 18
32°FApr 7Apr 2Mar 29Mar 26Mar 22Mar 18Mar 15Mar 11Mar 3
28°FMar 28Mar 23Mar 17Mar 13Mar 10Mar 6Mar 1Feb 24Feb 15
24°FMar 17Mar 10Mar 4Feb 28Feb 23Feb 17Feb 9Feb 2Jan 24
20°FMar 5Feb 27Feb 17Feb 10Feb 1Jan 28Jan 22Jan 15Jan 5
16°FFeb 26Feb 13Feb 4Jan 31Jan 27Jan 19Jan 14Jan 8Jan 1

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 19Oct 24Oct 27Oct 30Nov 1Nov 3Nov 6Nov 10Nov 15
32°FOct 29Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 23Nov 30
28°FNov 6Nov 12Nov 16Nov 20Nov 26Dec 1Dec 5Dec 12Dec 24
24°FNov 20Nov 30Dec 4Dec 10Dec 17Dec 23Dec 30Jan 5Jan 15
20°FDec 5Dec 14Dec 23Dec 29Jan 2Jan 7Jan 13Jan 19Feb 1
16°FDec 18Dec 30Jan 3Jan 8Jan 13Jan 17Jan 24Jan 30Feb 11

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°F233225220215212208204199192
32°F261252244239234229224218212
28°F295283276269262255249242232
24°F331320310303295289281272262
20°F365353343334328319311303292
16°F365365365365356346336328312

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
99% of years
20°F or colder
90% of years
16°F or colder
61% 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
2,578
Cooling degree days, base 65°F
2,012
Growing degree days, base 40°F
8,683
Growing degree days, base 45°F
7,043
Growing degree days, base 50°F
5,542
Growing degree days, base 55°F
4,198
Growing degree days, base 60°F
3,018

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January621161
February469384
March32917212
April12173408
May24213654
June1384832
July0493958
August0450914
September9283724
October11182440
November34511172
December548382

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 11 km from Prosperity. 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 USC00385200 (Little Mtn). Public domain.