Magdalena climate

Magdalena Frost Dates and Growing Season

NOAA 1991-2020 normals for Augustine 2E, 35 km from Magdalena, elevation 7000 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Augustine 2E. 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 May 19 and the first fall freeze around October 4, a growing season of about 137 days.

Median at 36°F
last May 31, first September 27
Median at 32°F
last May 19, first October 4
Median at 28°F
last May 8, first October 13

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 14Jun 9Jun 5Jun 2May 31May 29May 25May 21May 17
32°FJun 6May 31May 26May 22May 19May 16May 13May 10May 5
28°FMay 25May 18May 14May 11May 8May 5May 2Apr 29Apr 25
24°FMay 13May 7May 3May 1Apr 28Apr 24Apr 21Apr 17Apr 12
20°FMay 1Apr 25Apr 21Apr 16Apr 13Apr 10Apr 7Apr 3Mar 27
16°FApr 18Apr 10Apr 6Apr 2Mar 29Mar 24Mar 19Mar 15Mar 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°FSep 14Sep 19Sep 22Sep 25Sep 27Sep 29Oct 1Oct 3Oct 7
32°FSep 23Sep 27Sep 30Oct 2Oct 4Oct 6Oct 8Oct 12Oct 15
28°FOct 1Oct 4Oct 7Oct 10Oct 13Oct 15Oct 18Oct 20Oct 24
24°FOct 8Oct 13Oct 16Oct 19Oct 21Oct 24Oct 28Nov 1Nov 4
20°FOct 17Oct 22Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 13
16°FOct 26Oct 31Nov 3Nov 6Nov 8Nov 11Nov 15Nov 18Nov 22

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°F13513012612211811511110699
32°F156150146141137134130125117
28°F176169165161158153149145138
24°F196189185181178174170165157
20°F221213207203199195190184176
16°F248240234228224219213208201

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
5,980
Cooling degree days, base 65°F
290
Growing degree days, base 40°F
4,342
Growing degree days, base 45°F
3,183
Growing degree days, base 50°F
2,213
Growing degree days, base 55°F
1,407
Growing degree days, base 60°F
761

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03700
February83700
March75804
April536040
May2916202
June5570465
July8130587
August2174518
September14510317
October464077
November78003
December1,04900

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 35 km from Magdalena. 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 USC00290640 (Augustine 2E). Public domain.