Trinidad climate

Trinidad Frost Dates and Growing Season

NOAA 1991-2020 normals for Trinidad, 1.5 km from Trinidad, elevation 6030 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Trinidad. 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 30 and the first fall freeze around October 15, a growing season of about 167 days.

Median at 36°F
last May 8, first October 6
Median at 32°F
last April 30, first October 15
Median at 28°F
last April 19, first October 24

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 22May 17May 14May 11May 8May 6May 3Apr 30Apr 26
32°FMay 11May 7May 4May 2Apr 30Apr 28Apr 24Apr 21Apr 16
28°FMay 3Apr 30Apr 26Apr 22Apr 19Apr 16Apr 13Apr 8Apr 4
24°FApr 24Apr 18Apr 15Apr 11Apr 7Apr 4Mar 31Mar 26Mar 20
20°FApr 16Apr 8Apr 5Apr 1Mar 28Mar 23Mar 17Mar 10Mar 2
16°FApr 7Apr 1Mar 24Mar 18Mar 13Mar 8Mar 4Feb 26Feb 19

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 23Sep 28Oct 1Oct 3Oct 6Oct 8Oct 11Oct 14Oct 18
32°FOct 1Oct 7Oct 10Oct 12Oct 15Oct 18Oct 20Oct 23Oct 29
28°FOct 11Oct 16Oct 19Oct 21Oct 24Oct 27Oct 31Nov 3Nov 7
24°FOct 17Oct 21Oct 26Oct 31Nov 2Nov 5Nov 8Nov 12Nov 17
20°FOct 22Oct 29Nov 2Nov 6Nov 10Nov 14Nov 18Nov 21Nov 26
16°FOct 29Nov 4Nov 12Nov 16Nov 20Nov 22Nov 26Nov 29Dec 5

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°F166160157153149146140136128
32°F186180175171167163159155148
28°F207201196191187183179174166
24°F233225218214209204199194186
20°F256246240233228221216210201
16°F277268261254247242236228216

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
4,845
Cooling degree days, base 65°F
849
Growing degree days, base 40°F
5,821
Growing degree days, base 45°F
4,482
Growing degree days, base 50°F
3,322
Growing degree days, base 55°F
2,336
Growing degree days, base 60°F
1,512

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January90704
February759011
March611050
April4023137
May17444349
June20180610
July1288751
August5228688
September6998481
October3328197
November648040
December91705

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 1.5 km from Trinidad. 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 USC00058429 (Trinidad). Public domain.