Forest Ranch climate

Forest Ranch Frost Dates and Growing Season

NOAA 1991-2020 normals for De Sabla, 5.4 km from Forest Ranch, elevation 2710 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for De Sabla. 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 17 and the first fall freeze around November 11, a growing season of about 206 days.

Median at 36°F
last May 5, first October 28
Median at 32°F
last April 17, first November 11
Median at 28°F
last March 20, first November 27

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°FJun 1May 25May 16May 10May 5May 1Apr 27Apr 23Apr 17
32°FMay 11May 1Apr 26Apr 21Apr 17Apr 12Apr 8Apr 2Mar 23
28°FApr 20Apr 10Apr 3Mar 29Mar 20Mar 11Mar 3Feb 22Feb 5
24°FMar 23Mar 4Feb 24Feb 15Feb 3Jan 21Jan 8Dec 29Dec 13
20°FFeb 27Feb 16Jan 28Jan 15Jan 5Dec 31Dec 22Dec 15Dec 6
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 4Oct 13Oct 18Oct 23Oct 28Oct 31Nov 3Nov 6Nov 11
32°FOct 21Oct 31Nov 3Nov 7Nov 11Nov 15Nov 19Nov 23Nov 28
28°FNov 6Nov 13Nov 19Nov 23Nov 27Dec 1Dec 5Dec 11Dec 17
24°FNov 19Nov 28Dec 5Dec 12Dec 19Dec 26Jan 3Jan 18Feb 9
20°FDec 1Dec 11Dec 16Dec 22Dec 30Jan 4Jan 17Jan 30Feb 21
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°F199191184177171166158150137
32°F237226218212206200195186174
28°F300282271260252243235225213
24°F365357344334324314303289273
20°F365365365365365365365351334
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
100% of years
24°F or colder
84% of years
20°F or colder
29% of years
16°F or colder
5% 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
3,741
Cooling degree days, base 65°F
965
Growing degree days, base 40°F
6,449
Growing degree days, base 45°F
4,894
Growing degree days, base 50°F
3,588
Growing degree days, base 55°F
2,525
Growing degree days, base 60°F
1,656

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January650017
February557025
March512068
April3704135
May18739329
June52145544
July3302764
August2272735
September34166582
October19337321
November492065
December69005

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 5.4 km from Forest Ranch. 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 USC00042402 (De Sabla). Public domain.