Peculiar climate

Peculiar Frost Dates and Growing Season

NOAA 1991-2020 normals for Pleasant Hill WFO, 19.7 km from Peculiar, elevation 1000 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pleasant Hill WFO. 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 8 and the first fall freeze around October 29, a growing season of about 204 days.

Median at 36°F
last April 19, first October 19
Median at 32°F
last April 8, first October 29
Median at 28°F
last March 29, first November 7

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 2Apr 29Apr 25Apr 22Apr 19Apr 16Apr 12Apr 9Apr 4
32°FApr 23Apr 18Apr 13Apr 10Apr 8Apr 5Apr 2Mar 31Mar 24
28°FApr 12Apr 8Apr 4Mar 31Mar 29Mar 26Mar 22Mar 17Mar 9
24°FApr 3Mar 30Mar 26Mar 21Mar 18Mar 15Mar 10Mar 6Mar 1
20°FMar 26Mar 19Mar 15Mar 11Mar 7Mar 5Mar 2Feb 27Feb 20
16°FMar 17Mar 12Mar 7Mar 4Mar 2Feb 27Feb 23Feb 16Feb 9

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 5Oct 11Oct 14Oct 17Oct 19Oct 22Oct 24Oct 28Nov 1
32°FOct 16Oct 20Oct 24Oct 27Oct 29Nov 1Nov 3Nov 6Nov 12
28°FOct 25Oct 30Nov 1Nov 4Nov 7Nov 10Nov 14Nov 18Nov 24
24°FNov 2Nov 7Nov 11Nov 14Nov 17Nov 21Nov 26Nov 30Dec 5
20°FNov 10Nov 15Nov 19Nov 23Nov 28Dec 1Dec 4Dec 9Dec 16
16°FNov 17Nov 25Nov 30Dec 3Dec 6Dec 11Dec 16Dec 20Dec 27

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°F203196191187183179174169161
32°F224217212208204200195190182
28°F247239233228225220215210203
24°F267260253248244238233228220
20°F287279273267262257252247237
16°F307298291286280275270263255

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
4,922
Cooling degree days, base 65°F
1,387
Growing degree days, base 40°F
6,568
Growing degree days, base 45°F
5,260
Growing degree days, base 50°F
4,088
Growing degree days, base 55°F
3,052
Growing degree days, base 60°F
2,151

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08904
February858013
March629372
April32415201
May10499463
June7282726
July1417882
August1372835
September48167569
October27931257
November619157
December96208

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 19.7 km from Peculiar. 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 USC00236745 (Pleasant Hill WFO). Public domain.