Mount Olive climate

Mount Olive Frost Dates and Growing Season

NOAA 1991-2020 normals for Hillsboro, 22.6 km from Mount Olive, elevation 630 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hillsboro. 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 April 13 and the first fall freeze around October 24, a growing season of about 192 days.

Median at 36°F
last April 24, first October 13
Median at 32°F
last April 13, first October 24
Median at 28°F
last April 2, first November 2

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°FMay 11May 5May 1Apr 28Apr 24Apr 22Apr 19Apr 14Apr 9
32°FApr 28Apr 23Apr 19Apr 17Apr 13Apr 10Apr 7Apr 4Mar 30
28°FApr 18Apr 12Apr 8Apr 4Apr 2Mar 31Mar 28Mar 23Mar 17
24°FApr 5Apr 1Mar 29Mar 26Mar 22Mar 19Mar 15Mar 11Mar 3
20°FMar 29Mar 24Mar 19Mar 15Mar 12Mar 8Mar 4Feb 28Feb 23
16°FMar 21Mar 14Mar 11Mar 7Mar 3Feb 28Feb 24Feb 19Feb 10

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°FSep 27Oct 3Oct 7Oct 10Oct 13Oct 16Oct 19Oct 21Oct 26
32°FOct 10Oct 15Oct 18Oct 21Oct 24Oct 26Oct 29Oct 31Nov 4
28°FOct 21Oct 26Oct 29Nov 1Nov 2Nov 5Nov 8Nov 12Nov 20
24°FNov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 22Nov 27Dec 2
20°FNov 7Nov 12Nov 16Nov 20Nov 24Nov 29Dec 2Dec 7Dec 14
16°FNov 16Nov 22Nov 27Dec 1Dec 4Dec 7Dec 12Dec 18Dec 23

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°F189183178174170165161156148
32°F212204199195192188184179170
28°F237228223218214210206201192
24°F261252246241236231226221215
20°F282274267262257251247242234
16°F303294287281275270265259250

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
100% of years
20°F or colder
100% of years
16°F or colder
100% 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
4,799
Cooling degree days, base 65°F
1,389
Growing degree days, base 40°F
6,645
Growing degree days, base 45°F
5,334
Growing degree days, base 50°F
4,156
Growing degree days, base 55°F
3,104
Growing degree days, base 60°F
2,180

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08804
February842014
March631575
April29126235
May89120498
June7296739
July1393857
August1342806
September43169577
October26136275
November605267
December94209

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 22.6 km from Mount Olive. 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 USC00114108 (Hillsboro). Public domain.