Miller climate

Miller Frost Dates and Growing Season

NOAA 1991-2020 normals for Miller, 0.5 km from Miller, elevation 1576 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Miller. 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 3 and the first fall freeze around October 3, a growing season of about 152 days.

Median at 36°F
last May 14, first September 25
Median at 32°F
last May 3, first October 3
Median at 28°F
last April 24, first October 13

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 25May 22May 19May 16May 14May 11May 9May 5May 2
32°FMay 16May 12May 9May 6May 3May 1Apr 29Apr 25Apr 19
28°FMay 6May 2Apr 30Apr 28Apr 24Apr 21Apr 18Apr 15Apr 11
24°FApr 29Apr 25Apr 20Apr 17Apr 14Apr 11Apr 9Apr 6Apr 3
20°FApr 20Apr 15Apr 11Apr 8Apr 5Apr 3Apr 1Mar 28Mar 21
16°FApr 12Apr 7Apr 4Apr 1Mar 30Mar 27Mar 22Mar 17Mar 13

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 13Sep 18Sep 20Sep 23Sep 25Sep 28Sep 30Oct 3Oct 8
32°FSep 20Sep 25Sep 28Oct 1Oct 3Oct 6Oct 10Oct 14Oct 18
28°FSep 28Oct 2Oct 6Oct 10Oct 13Oct 17Oct 20Oct 22Oct 26
24°FOct 7Oct 12Oct 17Oct 20Oct 22Oct 25Oct 28Oct 31Nov 4
20°FOct 18Oct 22Oct 26Oct 29Oct 31Nov 3Nov 5Nov 9Nov 14
16°FOct 26Oct 31Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17Nov 22

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°F152145141137134130127123117
32°F169164159155152148145140134
28°F190184179175171168164158151
24°F208201197193190186181177170
20°F227219214210206202198194188
16°F246238232227223219214209202

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
7,840
Cooling degree days, base 65°F
653
Growing degree days, base 40°F
4,526
Growing degree days, base 45°F
3,510
Growing degree days, base 50°F
2,614
Growing degree days, base 55°F
1,835
Growing degree days, base 60°F
1,180

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,50000
February1,25301
March1,03407
April628154
May28924242
June60117508
July11251705
August23188631
September16567366
October558492
November96308
December1,35600

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 0.5 km from Miller. 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 USC00395561 (Miller). Public domain.