Upton climate

Upton Frost Dates and Growing Season

NOAA 1991-2020 normals for Upton, 1.5 km from Upton, elevation 4320 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Upton. 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 20 and the first fall freeze around September 23, a growing season of about 123 days.

Median at 36°F
last June 1, first September 13
Median at 32°F
last May 20, first September 23
Median at 28°F
last May 9, first October 2

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 20Jun 14Jun 8Jun 4Jun 1May 30May 26May 23May 19
32°FJun 4May 31May 27May 23May 20May 18May 15May 12May 8
28°FMay 24May 19May 15May 12May 9May 6May 4May 1Apr 26
24°FMay 12May 7May 4May 1Apr 29Apr 26Apr 22Apr 18Apr 13
20°FMay 2Apr 28Apr 24Apr 20Apr 16Apr 12Apr 8Apr 4Mar 30
16°FApr 24Apr 18Apr 13Apr 7Apr 3Apr 1Mar 28Mar 23Mar 17

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 30Sep 3Sep 7Sep 10Sep 13Sep 16Sep 19Sep 22Sep 26
32°FSep 7Sep 13Sep 16Sep 20Sep 23Sep 26Sep 28Oct 1Oct 5
28°FSep 16Sep 22Sep 26Sep 29Oct 2Oct 5Oct 8Oct 12Oct 15
24°FSep 26Oct 1Oct 4Oct 9Oct 13Oct 15Oct 17Oct 21Oct 24
20°FOct 3Oct 10Oct 14Oct 18Oct 20Oct 23Oct 26Oct 29Nov 2
16°FOct 12Oct 18Oct 22Oct 25Oct 28Nov 1Nov 3Nov 8Nov 14

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°F12111511010510197928677
32°F144136132127123119114108100
28°F165158153149145141136130120
24°F186180175170166162158153144
20°F207200195191186182177171164
16°F230222216211206201196189182

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
7,875
Cooling degree days, base 65°F
528
Growing degree days, base 40°F
4,085
Growing degree days, base 45°F
3,100
Growing degree days, base 50°F
2,258
Growing degree days, base 55°F
1,549
Growing degree days, base 60°F
973

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,36400
February1,16500
March94706
April668031
May3945152
June12268401
July16227676
August34184616
September20643311
October614162
November1,00504
December1,34100

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 1.5 km from Upton. 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 USC00489205 (Upton). Public domain.