LeChee climate

LeChee Frost Dates and Growing Season

NOAA 1991-2020 normals for Winslow Muni AP, 3 km from LeChee, elevation 4886 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Winslow Muni AP. 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 27 and the first fall freeze around October 18, a growing season of about 174 days.

Median at 36°F
last May 8, first October 9
Median at 32°F
last April 27, first October 18
Median at 28°F
last April 13, first October 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°FMay 26May 20May 16May 12May 8May 6May 3Apr 30Apr 25
32°FMay 14May 7May 3Apr 30Apr 27Apr 24Apr 21Apr 18Apr 12
28°FMay 1Apr 26Apr 21Apr 18Apr 13Apr 9Apr 6Apr 2Mar 27
24°FApr 19Apr 10Apr 5Apr 1Mar 28Mar 23Mar 17Mar 13Mar 7
20°FMar 31Mar 21Mar 15Mar 10Mar 7Mar 4Feb 28Feb 23Feb 14
16°FMar 8Mar 3Feb 27Feb 23Feb 18Feb 13Feb 8Feb 2Jan 27

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 28Oct 1Oct 4Oct 6Oct 9Oct 12Oct 15Oct 17Oct 21
32°FOct 5Oct 10Oct 13Oct 16Oct 18Oct 21Oct 23Oct 27Nov 1
28°FOct 13Oct 17Oct 21Oct 24Oct 27Oct 30Nov 2Nov 6Nov 10
24°FOct 20Oct 25Oct 29Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18
20°FOct 30Nov 6Nov 9Nov 13Nov 16Nov 18Nov 22Nov 25Nov 30
16°FNov 9Nov 15Nov 20Nov 23Nov 26Nov 29Dec 1Dec 6Dec 13

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°F171164159156152148144139132
32°F193187182178174169166160153
28°F216209205199196192187181173
24°F247238231227222216211206199
20°F277267262256252247241235224
16°F311300294287281275269263255

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
4,330
Cooling degree days, base 65°F
1,329
Growing degree days, base 40°F
6,601
Growing degree days, base 45°F
5,215
Growing degree days, base 50°F
4,001
Growing degree days, base 55°F
2,958
Growing degree days, base 60°F
2,069

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January90201
February67108
March522058
April3074179
May10666427
June8270713
July0439904
August0375840
September24165591
October25410244
November612033
December92402

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 km from LeChee. 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 USW00023194 (Winslow Muni AP). Public domain.