Maplewood climate

Maplewood Frost Dates and Growing Season

NOAA 1991-2020 normals for St Paul Downtown AP, 5.3 km from Maplewood, elevation 700 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for St Paul Downtown AP. 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 24 and the first fall freeze around October 16, a growing season of about 174 days.

Median at 36°F
last May 4, first October 5
Median at 32°F
last April 24, first October 16
Median at 28°F
last April 13, first October 27

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 18May 13May 10May 7May 4May 1Apr 29Apr 25Apr 20
32°FMay 10May 4Apr 30Apr 27Apr 24Apr 21Apr 18Apr 15Apr 9
28°FApr 28Apr 23Apr 19Apr 16Apr 13Apr 10Apr 7Apr 4Apr 1
24°FApr 17Apr 13Apr 9Apr 6Apr 4Apr 3Mar 31Mar 27Mar 22
20°FApr 10Apr 4Apr 2Mar 31Mar 28Mar 24Mar 21Mar 17Mar 12
16°FApr 2Mar 30Mar 26Mar 23Mar 19Mar 16Mar 13Mar 9Mar 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 23Sep 27Sep 30Oct 2Oct 5Oct 7Oct 11Oct 14Oct 19
32°FOct 2Oct 6Oct 10Oct 13Oct 16Oct 19Oct 22Oct 25Oct 29
28°FOct 11Oct 17Oct 21Oct 24Oct 27Oct 29Nov 1Nov 4Nov 8
24°FOct 22Oct 28Oct 31Nov 2Nov 4Nov 7Nov 10Nov 13Nov 18
20°FNov 1Nov 4Nov 7Nov 10Nov 12Nov 15Nov 19Nov 22Nov 27
16°FNov 7Nov 11Nov 14Nov 18Nov 21Nov 23Nov 26Nov 29Dec 4

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°F172166161157153149146141134
32°F193187183178174169166161154
28°F213208202198194191187181174
24°F233226221217212209204199193
20°F250243238233229225220216209
16°F265257253248245241236231224

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
7,443
Cooling degree days, base 65°F
724
Growing degree days, base 40°F
4,821
Growing degree days, base 45°F
3,774
Growing degree days, base 50°F
2,831
Growing degree days, base 55°F
2,005
Growing degree days, base 60°F
1,300

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51100
February1,23800
March988012
April543379
May22536293
June35150565
July5262722
August10198652
September13370393
October5037104
November91209
December1,34200

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 5.3 km from Maplewood. 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 USW00014927 (St Paul Downtown AP). Public domain.