Chester climate

Chester Frost Dates and Growing Season

NOAA 1991-2020 normals for Chester, 0.9 km from Chester, elevation 4530 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chester. 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 28 and the first fall freeze around September 28, a growing season of about 124 days.

Median at 36°F
last June 15, first September 12
Median at 32°F
last May 28, first September 28
Median at 28°F
last May 2, first October 18

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

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°F112104100958985807364
32°F149140133129124118113108100
28°F187180174169163159154148138
24°F226219213208203199193186176
20°F265254247242237231226219212
16°F298289280273268263256247235

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
6,512
Cooling degree days, base 65°F
210
Growing degree days, base 40°F
3,779
Growing degree days, base 45°F
2,713
Growing degree days, base 50°F
1,837
Growing degree days, base 55°F
1,133
Growing degree days, base 60°F
580

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02300
February86000
March82501
April640017
May4132123
June18525300
July36103532
August4767485
September17114300
October481077
November79502
December1,03700

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 0.9 km from Chester. 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 USC00041700 (Chester). Public domain.