Nogales climate

Nogales Frost Dates and Growing Season

NOAA 1991-2020 normals for Nogales 6 N, 13.2 km from Nogales, elevation 3461 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Nogales 6 N. 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 16 and the first fall freeze around November 2, a growing season of about 199 days.

Median at 36°F
last May 2, first October 24
Median at 32°F
last April 16, first November 2
Median at 28°F
last March 22, first November 14

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 18May 13May 9May 5May 2Apr 30Apr 27Apr 22Apr 18
32°FMay 4Apr 29Apr 24Apr 20Apr 16Apr 12Apr 8Apr 3Mar 28
28°FApr 15Apr 8Apr 3Mar 28Mar 22Mar 16Mar 10Mar 4Feb 26
24°FMar 23Mar 12Mar 6Mar 2Feb 27Feb 22Feb 17Feb 10Jan 31
20°FMar 1Feb 23Feb 16Feb 10Feb 3Jan 30Jan 21Jan 10Dec 29
16°FFeb 17Feb 5Jan 31Jan 24Jan 16Jan 8Dec 31Dec 23Dec 13

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 10Oct 15Oct 19Oct 21Oct 24Oct 27Oct 30Nov 2Nov 6
32°FOct 19Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 11Nov 16
28°FOct 29Nov 2Nov 7Nov 10Nov 14Nov 17Nov 20Nov 23Nov 29
24°FNov 8Nov 15Nov 19Nov 22Nov 25Nov 29Dec 2Dec 5Dec 12
20°FNov 22Nov 27Dec 1Dec 6Dec 10Dec 14Dec 19Dec 27Jan 9
16°FDec 4Dec 10Dec 15Dec 21Dec 27Jan 1Jan 9Jan 24Feb 1

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°F192186180176171167163159151
32°F222214208203199195190184175
28°F262252245239233226220213205
24°F303291282276269263257249238
20°F346334326318309303295287274
16°F365365365358349341333324311

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
97% of years
16°F or colder
65% 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
2,596
Cooling degree days, base 65°F
1,665
Growing degree days, base 40°F
8,232
Growing degree days, base 45°F
6,522
Growing degree days, base 50°F
4,976
Growing degree days, base 55°F
3,659
Growing degree days, base 60°F
2,564

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January564028
February452051
March3451154
April18014289
May49107523
June1343792
July0460925
August0408873
September2272720
October8758438
November3352156
December580028

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 13.2 km from Nogales. 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 USC00025924 (Nogales 6 N). Public domain.