Platte climate

Platte Frost Dates and Growing Season

NOAA 1991-2020 normals for Academy 2NE, 21 km from Platte, elevation 1681 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Academy 2NE. 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 8, a growing season of about 159 days.

Median at 36°F
last May 9, first September 29
Median at 32°F
last April 30, first October 8
Median at 28°F
last April 19, first October 18

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 24May 19May 15May 12May 9May 6May 4May 2Apr 28
32°FMay 14May 8May 5May 2Apr 30Apr 28Apr 24Apr 20Apr 16
28°FMay 4Apr 30Apr 26Apr 23Apr 19Apr 17Apr 13Apr 10Apr 6
24°FApr 25Apr 20Apr 17Apr 13Apr 10Apr 7Apr 4Apr 1Mar 24
20°FApr 17Apr 11Apr 7Apr 3Apr 1Mar 28Mar 24Mar 19Mar 13
16°FApr 8Apr 2Mar 30Mar 25Mar 21Mar 18Mar 14Mar 10Mar 4

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 21Sep 24Sep 27Sep 29Oct 1Oct 4Oct 7Oct 11
32°FSep 24Sep 29Oct 1Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21
28°FOct 1Oct 8Oct 12Oct 16Oct 18Oct 21Oct 24Oct 27Nov 1
24°FOct 13Oct 18Oct 22Oct 25Oct 27Oct 30Nov 2Nov 5Nov 11
20°FOct 23Oct 28Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 19
16°FOct 31Nov 4Nov 7Nov 11Nov 13Nov 16Nov 19Nov 23Nov 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°F159153149146142139135131123
32°F178171167163159156152147141
28°F200193188183178175170165159
24°F219212206203198193189183175
20°F240231225221217213208203194
16°F258250244239235230223218211

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
7,117
Cooling degree days, base 65°F
859
Growing degree days, base 40°F
4,999
Growing degree days, base 45°F
3,923
Growing degree days, base 50°F
2,968
Growing degree days, base 55°F
2,138
Growing degree days, base 60°F
1,434

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,38600
February1,13802
March931019
April564377
May25635276
June44158564
July7311769
August15247697
September13298424
October4938122
November885018
December1,26801

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 21 km from Platte. 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 USC00390043 (Academy 2NE). Public domain.