Parker climate

Parker Frost Dates and Growing Season

NOAA 1991-2020 normals for Bridgewater, 34.1 km from Parker, elevation 1417 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bridgewater. 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 30 and the first fall freeze around October 7, a growing season of about 161 days.

Median at 36°F
last May 7, first September 30
Median at 32°F
last April 30, first October 7
Median at 28°F
last April 19, first October 19

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 22May 16May 13May 11May 7May 5May 2Apr 30Apr 26
32°FMay 11May 6May 3May 1Apr 30Apr 26Apr 23Apr 20Apr 15
28°FMay 2Apr 29Apr 25Apr 23Apr 19Apr 17Apr 13Apr 10Apr 6
24°FApr 23Apr 19Apr 16Apr 13Apr 10Apr 7Apr 5Apr 2Mar 28
20°FApr 17Apr 11Apr 7Apr 5Apr 2Mar 31Mar 27Mar 23Mar 16
16°FApr 9Apr 4Mar 31Mar 29Mar 25Mar 21Mar 18Mar 13Mar 8

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 17Sep 22Sep 25Sep 27Sep 30Oct 1Oct 4Oct 6Oct 11
32°FSep 25Sep 30Oct 1Oct 4Oct 7Oct 10Oct 13Oct 16Oct 21
28°FOct 3Oct 9Oct 13Oct 16Oct 19Oct 21Oct 24Oct 26Oct 31
24°FOct 15Oct 19Oct 23Oct 25Oct 28Oct 30Nov 1Nov 5Nov 10
20°FOct 23Oct 28Oct 31Nov 2Nov 5Nov 8Nov 10Nov 14Nov 18
16°FOct 31Nov 3Nov 7Nov 10Nov 13Nov 15Nov 18Nov 21Nov 27

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°F162155151147143141137132126
32°F178173169165161157153149144
28°F200193188184181177172167160
24°F217210205202198195191187181
20°F235228222218214211206201194
16°F255246240235230226221216210

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
7,504
Cooling degree days, base 65°F
780
Growing degree days, base 40°F
4,837
Growing degree days, base 45°F
3,788
Growing degree days, base 50°F
2,858
Growing degree days, base 55°F
2,044
Growing degree days, base 60°F
1,351

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,48900
February1,21501
March991011
April576371
May24939284
June38169582
July7281739
August14207659
September14276393
October5066107
November932011
December1,34700

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 34.1 km from Parker. 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 USC00391032 (Bridgewater). Public domain.