Lompico climate

Lompico Frost Dates and Growing Season

NOAA 1991-2020 normals for Ben Lomond #4, 3.3 km from Lompico, elevation 420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ben Lomond #4. 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 25 and the first fall freeze around November 11, a growing season of about 231 days.

Median at 36°F
last April 28, first October 21
Median at 32°F
last March 25, first November 11
Median at 28°F
last February 6, first December 4

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 19May 11May 5Apr 30Apr 28Apr 23Apr 18Apr 13Apr 6
32°FApr 21Apr 12Apr 4Mar 31Mar 25Mar 17Mar 10Feb 28Feb 17
28°FMar 9Feb 28Feb 22Feb 15Feb 6Jan 30Jan 22Jan 8Dec 26
24°FFeb 13Jan 31Jan 21Jan 13Jan 4Dec 31Dec 27Dec 20Dec 13
20°FJan 14Jan 4Jan 2Dec 31Dec 30Dec 25Dec 20Dec 14Dec 8
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°FOct 1Oct 6Oct 12Oct 17Oct 21Oct 26Nov 1Nov 5Nov 11
32°FOct 18Oct 26Nov 1Nov 6Nov 11Nov 16Nov 21Nov 27Dec 4
28°FNov 11Nov 19Nov 25Nov 30Dec 4Dec 8Dec 15Dec 25Jan 7
24°FDec 1Dec 6Dec 11Dec 16Dec 20Dec 27Jan 1Jan 10Jan 23
20°FDec 6Dec 11Dec 18Dec 22Dec 27Dec 31Jan 1Jan 3Jan 11
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°F207197190184179172166156144
32°F272257247239231224216208197
28°F344331322311302295286274262
24°F365365365364355347339332317
20°F365365365365365365365365362
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
100% of years
28°F or colder
96% of years
24°F or colder
57% of years
20°F or colder
11% of years
16°F or colder
0% 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
2,286
Cooling degree days, base 65°F
641
Growing degree days, base 40°F
7,482
Growing degree days, base 45°F
5,677
Growing degree days, base 50°F
3,982
Growing degree days, base 55°F
2,544
Growing degree days, base 60°F
1,435

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January434075
February3390106
March2941185
April20711256
May11239392
June3091511
July6147606
August4166628
September17130563
October9552422
November2904178
December457059

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 3.3 km from Lompico. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00040673 (Ben Lomond #4). Public domain.