Marissa climate

Marissa Frost Dates and Growing Season

NOAA 1991-2020 normals for Sparta 1 W, 15.1 km from Marissa, elevation 535 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sparta 1 W. 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 12 and the first fall freeze around October 22, a growing season of about 191 days.

Median at 36°F
last April 24, first October 12
Median at 32°F
last April 12, first October 22
Median at 28°F
last April 1, first November 1

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 11May 5May 1Apr 28Apr 24Apr 21Apr 18Apr 14Apr 10
32°FApr 29Apr 23Apr 19Apr 15Apr 12Apr 10Apr 7Apr 2Mar 29
28°FApr 16Apr 10Apr 7Apr 3Apr 1Mar 29Mar 26Mar 22Mar 16
24°FApr 4Mar 31Mar 27Mar 24Mar 20Mar 17Mar 13Mar 9Mar 4
20°FMar 25Mar 20Mar 17Mar 14Mar 10Mar 6Mar 3Feb 28Feb 20
16°FMar 19Mar 13Mar 8Mar 5Mar 2Feb 27Feb 22Feb 15Feb 7

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 27Oct 2Oct 5Oct 9Oct 12Oct 15Oct 17Oct 19Oct 23
32°FOct 7Oct 13Oct 17Oct 19Oct 22Oct 24Oct 26Oct 29Nov 2
28°FOct 19Oct 23Oct 27Oct 30Nov 1Nov 3Nov 6Nov 9Nov 16
24°FOct 29Nov 2Nov 6Nov 9Nov 13Nov 16Nov 21Nov 27Dec 2
20°FNov 8Nov 13Nov 17Nov 22Nov 26Nov 30Dec 3Dec 7Dec 15
16°FNov 18Nov 25Dec 1Dec 4Dec 7Dec 11Dec 16Dec 22Dec 28

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°F187181176171166162159155147
32°F210203198195191186182176168
28°F235227222217213209205200193
24°F262254247241237233228221214
20°F286277270265261257252246239
16°F310300293288282276271264255

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
4,833
Cooling degree days, base 65°F
1,244
Growing degree days, base 40°F
6,412
Growing degree days, base 45°F
5,109
Growing degree days, base 50°F
3,944
Growing degree days, base 55°F
2,914
Growing degree days, base 60°F
2,008

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05805
February83609
March644472
April31919211
May104101465
June9260700
July1362826
August3319781
September57149544
October27528255
November598365
December930011

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 15.1 km from Marissa. 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 USC00118147 (Sparta 1 W). Public domain.