Vega climate

Vega Frost Dates and Growing Season

NOAA 1991-2020 normals for Boys Rch, 35.5 km from Vega, elevation 3191 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Boys Rch. 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 19 and the first fall freeze around October 23, a growing season of about 183 days.

Median at 36°F
last April 29, first October 13
Median at 32°F
last April 19, first October 23
Median at 28°F
last April 8, first November 1

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 11May 6May 3May 1Apr 29Apr 26Apr 23Apr 20Apr 15
32°FMay 2Apr 28Apr 25Apr 22Apr 19Apr 16Apr 13Apr 10Apr 4
28°FApr 24Apr 19Apr 15Apr 11Apr 8Apr 5Apr 1Mar 29Mar 22
24°FApr 14Apr 8Apr 3Mar 31Mar 28Mar 24Mar 19Mar 16Mar 10
20°FApr 2Mar 28Mar 23Mar 18Mar 14Mar 11Mar 6Mar 2Feb 25
16°FMar 19Mar 12Mar 7Mar 3Feb 28Feb 26Feb 21Feb 16Feb 10

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 1Oct 5Oct 8Oct 11Oct 13Oct 16Oct 18Oct 21Oct 24
32°FOct 10Oct 14Oct 17Oct 20Oct 23Oct 24Oct 26Oct 29Nov 2
28°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 3Nov 5Nov 7Nov 11
24°FOct 26Oct 31Nov 3Nov 5Nov 7Nov 10Nov 13Nov 16Nov 20
20°FNov 1Nov 6Nov 10Nov 13Nov 16Nov 19Nov 21Nov 24Nov 30
16°FNov 9Nov 15Nov 19Nov 22Nov 25Nov 28Dec 1Dec 4Dec 10

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°F183177173169165162159154149
32°F202195190187183179176171165
28°F225217212208204199194190183
24°F248240234229224220215210204
20°F267261257252247243237231223
16°F293285279273269265260254246

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
4,034
Cooling degree days, base 65°F
1,609
Growing degree days, base 40°F
7,174
Growing degree days, base 45°F
5,752
Growing degree days, base 50°F
4,481
Growing degree days, base 55°F
3,374
Growing degree days, base 60°F
2,421

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January85905
February671021
March4874105
April25322251
May76130522
June3350798
July0462927
August0406871
September32203622
October23330288
November559165
December86207

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 35.5 km from Vega. 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 USC00411000 (Boys Rch). Public domain.