Marshfield climate

Marshfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Marshfield 4 Wsw, 6.9 km from Marshfield, elevation 1414 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Marshfield 4 Wsw. 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 13 and the first fall freeze around October 24, a growing season of about 191 days.

Median at 36°F
last April 25, first October 14
Median at 32°F
last April 13, first October 24
Median at 28°F
last April 1, 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°FMay 8May 3May 1Apr 28Apr 25Apr 22Apr 17Apr 13Apr 7
32°FApr 29Apr 24Apr 20Apr 16Apr 13Apr 9Apr 5Apr 2Mar 29
28°FApr 19Apr 13Apr 8Apr 4Apr 1Mar 30Mar 27Mar 23Mar 17
24°FApr 6Apr 1Mar 29Mar 26Mar 23Mar 19Mar 16Mar 12Mar 5
20°FMar 30Mar 24Mar 20Mar 16Mar 13Mar 8Mar 5Mar 1Feb 23
16°FMar 20Mar 14Mar 10Mar 6Mar 3Feb 28Feb 24Feb 18Feb 11

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 29Oct 5Oct 8Oct 12Oct 14Oct 17Oct 20Oct 23Oct 28
32°FOct 8Oct 14Oct 18Oct 22Oct 24Oct 27Oct 30Nov 1Nov 6
28°FOct 19Oct 24Oct 28Oct 31Nov 2Nov 5Nov 8Nov 12Nov 17
24°FOct 30Nov 3Nov 6Nov 10Nov 13Nov 15Nov 19Nov 23Nov 28
20°FNov 5Nov 11Nov 15Nov 19Nov 22Nov 26Nov 30Dec 3Dec 9
16°FNov 14Nov 20Nov 25Nov 29Dec 1Dec 5Dec 10Dec 16Dec 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°F192185180176172167163158151
32°F214206201197191187182177169
28°F236227222217213209206201192
24°F257250244239234229225219211
20°F279270265260254250244238230
16°F301291284278273268263257247

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
4,689
Cooling degree days, base 65°F
1,310
Growing degree days, base 40°F
6,587
Growing degree days, base 45°F
5,251
Growing degree days, base 50°F
4,055
Growing degree days, base 55°F
2,999
Growing degree days, base 60°F
2,084

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02707
February805017
March608379
April30722222
May10594458
June9254694
July1386851
August2356818
September51161562
October27031266
November599267
December905013

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 6.9 km from Marshfield. 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 USC00235307 (Marshfield 4 Wsw). Public domain.