Lefors climate

Lefors Frost Dates and Growing Season

NOAA 1991-2020 normals for Pampa #2, 20.1 km from Lefors, elevation 3150 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pampa #2. 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 14 and the first fall freeze around October 28, a growing season of about 194 days.

Median at 36°F
last April 24, first October 19
Median at 32°F
last April 14, first October 28
Median at 28°F
last April 4, first November 5

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 6May 2Apr 30Apr 27Apr 24Apr 21Apr 18Apr 15Apr 9
32°FApr 29Apr 23Apr 20Apr 18Apr 14Apr 11Apr 7Apr 3Mar 28
28°FApr 21Apr 16Apr 10Apr 7Apr 4Apr 1Mar 28Mar 23Mar 15
24°FApr 9Apr 3Mar 31Mar 26Mar 21Mar 16Mar 12Mar 7Mar 3
20°FMar 30Mar 21Mar 16Mar 11Mar 8Mar 4Mar 1Feb 25Feb 18
16°FMar 16Mar 9Mar 4Mar 1Feb 27Feb 22Feb 17Feb 12Jan 31

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 10Oct 13Oct 16Oct 19Oct 21Oct 24Oct 26Oct 31
32°FOct 13Oct 19Oct 22Oct 25Oct 28Oct 31Nov 2Nov 5Nov 9
28°FOct 22Oct 27Oct 31Nov 3Nov 5Nov 7Nov 10Nov 13Nov 18
24°FOct 30Nov 4Nov 7Nov 10Nov 13Nov 16Nov 20Nov 24Nov 29
20°FNov 6Nov 11Nov 15Nov 19Nov 23Nov 26Nov 30Dec 3Dec 10
16°FNov 14Nov 21Nov 25Nov 29Dec 2Dec 6Dec 11Dec 16Dec 24

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°F194189184181177172168163157
32°F216208203198194191186182174
28°F237229224219215210205199193
24°F259253246241236230225219210
20°F282274268263257251245239229
16°F313303294287280274269262251

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
4,175
Cooling degree days, base 65°F
1,600
Growing degree days, base 40°F
7,142
Growing degree days, base 45°F
5,727
Growing degree days, base 50°F
4,464
Growing degree days, base 55°F
3,360
Growing degree days, base 60°F
2,409

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January877010
February710023
March5304101
April28123239
May92120497
June7320763
July1461925
August2419882
September36212627
October23439304
November554280
December851012

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 20.1 km from Lefors. 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 USC00416776 (Pampa #2). Public domain.