Parker climate

Parker Frost Dates and Growing Season

NOAA 1991-2020 normals for Clarion 3 Sw, 23.3 km from Parker, elevation 1040 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clarion 3 Sw. 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 9 and the first fall freeze around October 11, a growing season of about 154 days.

Median at 36°F
last May 20, first October 2
Median at 32°F
last May 9, first October 11
Median at 28°F
last April 29, first October 24

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

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°F153147142138134130126121114
32°F174167162159154151147141135
28°F197191186182178174169164157
24°F223216211206202198193189179
20°F251243238234229224220214207
16°F275267261255250245240234226

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
6,709
Cooling degree days, base 65°F
448
Growing degree days, base 40°F
4,502
Growing degree days, base 45°F
3,409
Growing degree days, base 50°F
2,453
Growing degree days, base 55°F
1,635
Growing degree days, base 60°F
958

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,25801
February1,09300
March950011
April559166
May26225256
June6787470
July16158608
August24131572
September14143357
October4703101
November783011
December1,08502

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 23.3 km from Parker. 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 USC00361485 (Clarion 3 Sw). Public domain.