Harvey climate

Harvey Frost Dates and Growing Season

NOAA 1991-2020 normals for Marquette, 6 km from Harvey, elevation 665 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Marquette. 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 8 and the first fall freeze around October 21, a growing season of about 164 days.

Median at 36°F
last May 23, first October 8
Median at 32°F
last May 8, first October 21
Median at 28°F
last April 27, first November 2

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 6Jun 1May 29May 26May 23May 19May 16May 13May 7
32°FMay 23May 18May 15May 11May 8May 5May 2Apr 30Apr 26
28°FMay 11May 5May 1Apr 29Apr 27Apr 24Apr 21Apr 17Apr 11
24°FApr 29Apr 25Apr 21Apr 17Apr 14Apr 11Apr 8Apr 4Apr 1
20°FApr 18Apr 13Apr 9Apr 6Apr 4Apr 1Mar 30Mar 26Mar 20
16°FApr 10Apr 6Apr 3Mar 31Mar 28Mar 25Mar 21Mar 17Mar 12

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 26Sep 30Oct 3Oct 6Oct 8Oct 11Oct 14Oct 18Oct 23
32°FOct 6Oct 11Oct 15Oct 18Oct 21Oct 25Oct 28Nov 1Nov 5
28°FOct 19Oct 25Oct 29Oct 31Nov 2Nov 4Nov 7Nov 11Nov 16
24°FOct 31Nov 3Nov 6Nov 9Nov 11Nov 13Nov 16Nov 20Nov 25
20°FNov 6Nov 11Nov 14Nov 16Nov 19Nov 22Nov 25Nov 29Dec 4
16°FNov 14Nov 18Nov 23Nov 26Nov 28Dec 1Dec 4Dec 9Dec 16

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°F159151146141137133129125119
32°F185178173168164159155149142
28°F208201196191187183179174166
24°F230223218214210207203198189
20°F248242238234230226222218210
16°F266259254249246241237233226

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
8,398
Cooling degree days, base 65°F
270
Growing degree days, base 40°F
3,477
Growing degree days, base 45°F
2,560
Growing degree days, base 50°F
1,776
Growing degree days, base 55°F
1,124
Growing degree days, base 60°F
615

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,44100
February1,26800
March1,14203
April798016
May4796107
June21333282
July69104501
August5693502
September19831295
October561266
November91405
December1,25900

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 6 km from Harvey. 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 USW00014838 (Marquette). Public domain.