Peru climate

Peru Frost Dates and Growing Season

NOAA 1991-2020 normals for Rumford 1 Sse, 10.8 km from Peru, elevation 630 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rumford 1 Sse. 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 4 and the first fall freeze around October 6, a growing season of about 155 days.

Median at 36°F
last May 17, first September 28
Median at 32°F
last May 4, first October 6
Median at 28°F
last April 22, first October 18

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

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 17Sep 21Sep 23Sep 26Sep 28Oct 1Oct 2Oct 5Oct 9
32°FSep 26Sep 30Oct 1Oct 4Oct 6Oct 9Oct 11Oct 15Oct 20
28°FOct 5Oct 9Oct 12Oct 15Oct 18Oct 22Oct 25Oct 29Nov 2
24°FOct 17Oct 22Oct 26Oct 29Nov 1Nov 2Nov 5Nov 9Nov 13
20°FOct 30Nov 3Nov 6Nov 10Nov 12Nov 15Nov 17Nov 21Nov 25
16°FNov 10Nov 14Nov 17Nov 20Nov 23Nov 26Nov 28Dec 1Dec 5

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°F148143139136133129125121115
32°F171165161158155152148143137
28°F197190186182178174170167160
24°F219213208205202198194190183
20°F238233229226222219215210204
16°F257251246243240236233228223

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
7,952
Cooling degree days, base 65°F
329
Growing degree days, base 40°F
3,913
Growing degree days, base 45°F
2,934
Growing degree days, base 50°F
2,078
Growing degree days, base 55°F
1,348
Growing degree days, base 60°F
757

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,48300
February1,28800
March1,12200
April685122
May32411185
June10261411
July21131575
August38100527
September18725296
October552158
November89105
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 10.8 km from Peru. 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 USC00177325 (Rumford 1 Sse). Public domain.