Mora climate

Mora Frost Dates and Growing Season

NOAA 1991-2020 normals for Mora, 1.6 km from Mora, elevation 1018 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mora. 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 September 30, a growing season of about 142 days.

Median at 36°F
last May 21, first September 21
Median at 32°F
last May 9, first September 30
Median at 28°F
last April 28, first October 9

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 3May 31May 28May 25May 21May 18May 14May 11May 6
32°FMay 26May 20May 16May 12May 9May 6May 3Apr 30Apr 26
28°FMay 14May 8May 4Apr 30Apr 28Apr 26Apr 23Apr 19Apr 14
24°FMay 1Apr 26Apr 23Apr 19Apr 17Apr 14Apr 11Apr 8Apr 3
20°FApr 20Apr 15Apr 12Apr 9Apr 6Apr 4Apr 2Mar 30Mar 23
16°FApr 12Apr 8Apr 5Apr 2Mar 31Mar 28Mar 24Mar 20Mar 14

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 7Sep 12Sep 16Sep 18Sep 21Sep 23Sep 26Sep 30Oct 3
32°FSep 17Sep 21Sep 24Sep 27Sep 30Oct 1Oct 4Oct 7Oct 12
28°FSep 24Sep 29Oct 2Oct 5Oct 9Oct 12Oct 16Oct 19Oct 24
24°FOct 3Oct 10Oct 15Oct 18Oct 21Oct 25Oct 29Nov 1Nov 5
20°FOct 16Oct 22Oct 28Oct 31Nov 2Nov 4Nov 7Nov 10Nov 16
16°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 12Nov 15Nov 19Nov 24

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°F141134130126122118114109102
32°F161155150145142138135130123
28°F184176171166163158154149142
24°F207200195190185181176170164
20°F227220215211208203199193184
16°F244237232227223219215210204

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
8,721
Cooling degree days, base 65°F
390
Growing degree days, base 40°F
3,941
Growing degree days, base 45°F
2,986
Growing degree days, base 50°F
2,148
Growing degree days, base 55°F
1,427
Growing degree days, base 60°F
834

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,68600
February1,39300
March1,14304
April688136
May32818202
June8978441
July25154594
August43105527
September22233282
October609258
November1,02304
December1,47200

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 1.6 km from Mora. 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 USC00215615 (Mora). Public domain.