Maltby climate

Maltby Frost Dates and Growing Season

NOAA 1991-2020 normals for Monroe, 9.9 km from Maltby, elevation 120 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Monroe. 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 17 and the first fall freeze around October 23, a growing season of about 188 days.

Median at 36°F
last May 5, first October 6
Median at 32°F
last April 17, first October 23
Median at 28°F
last March 26, first November 8

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 20May 15May 11May 8May 5May 2Apr 29Apr 26Apr 20
32°FMay 7May 1Apr 27Apr 22Apr 17Apr 12Apr 8Apr 3Mar 29
28°FApr 14Apr 7Apr 2Mar 29Mar 26Mar 22Mar 17Mar 13Mar 6
24°FMar 22Mar 15Mar 10Mar 4Feb 28Feb 25Feb 19Feb 13Jan 31
20°FFeb 28Feb 24Feb 18Feb 11Feb 2Jan 23Jan 8Dec 30Dec 10
16°FFeb 18Feb 6Jan 27Jan 14Jan 4Dec 25Dec 13Dec 8Nov 30

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 21Sep 27Oct 1Oct 3Oct 6Oct 10Oct 14Oct 18Oct 25
32°FOct 7Oct 13Oct 16Oct 20Oct 23Oct 27Oct 31Nov 4Nov 9
28°FOct 20Oct 27Nov 1Nov 4Nov 8Nov 11Nov 14Nov 20Nov 26
24°FNov 1Nov 9Nov 14Nov 18Nov 23Nov 28Dec 3Dec 10Dec 22
20°FNov 13Nov 20Nov 27Dec 2Dec 9Dec 16Dec 26Jan 3Jan 26
16°FNov 19Nov 28Dec 4Dec 9Dec 15Dec 24Jan 2Jan 15Feb 1

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°F176169163158153149145139132
32°F212204198193188182177171163
28°F253242236231225219214206197
24°F310295284275268261255248235
20°F361343333325318310302290274
16°F365365365365357343334325313

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
89% of years
16°F or colder
54% 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
5,696
Cooling degree days, base 65°F
67
Growing degree days, base 40°F
3,871
Growing degree days, base 45°F
2,559
Growing degree days, base 50°F
1,550
Growing degree days, base 55°F
801
Growing degree days, base 60°F
297

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January83601
February70401
March67007
April510032
May3431140
June2076250
July9129403
August8526406
September2104247
October482058
November69305
December86500

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 9.9 km from Maltby. 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 USC00455525 (Monroe). Public domain.