Roaring Spring climate

Roaring Spring Frost Dates and Growing Season

NOAA 1991-2020 normals for Altoona 7 Sw, 9.5 km from Roaring Spring, elevation 1180 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Altoona 7 Sw. 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 25 and the first fall freeze around October 20, a growing season of about 177 days.

Median at 36°F
last May 6, first October 8
Median at 32°F
last April 25, first October 20
Median at 28°F
last April 12, 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 23May 18May 14May 10May 6May 3Apr 30Apr 26Apr 21
32°FMay 14May 7May 2Apr 28Apr 25Apr 22Apr 18Apr 15Apr 10
28°FMay 1Apr 23Apr 18Apr 15Apr 12Apr 9Apr 6Apr 3Mar 30
24°FApr 13Apr 8Apr 5Apr 3Mar 31Mar 29Mar 26Mar 22Mar 17
20°FApr 1Mar 30Mar 26Mar 23Mar 20Mar 17Mar 14Mar 10Mar 5
16°FMar 24Mar 20Mar 17Mar 13Mar 10Mar 7Mar 4Feb 28Feb 21

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 28Oct 1Oct 4Oct 6Oct 8Oct 11Oct 14Oct 17Oct 22
32°FOct 6Oct 10Oct 14Oct 17Oct 20Oct 23Oct 25Oct 30Nov 3
28°FOct 16Oct 22Oct 25Oct 28Nov 1Nov 2Nov 6Nov 11Nov 17
24°FOct 29Nov 2Nov 6Nov 10Nov 14Nov 17Nov 21Nov 26Dec 1
20°FNov 9Nov 16Nov 19Nov 24Nov 28Dec 1Dec 4Dec 8Dec 16
16°FNov 21Nov 28Dec 2Dec 6Dec 10Dec 15Dec 19Dec 25Dec 31

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°F175169164160156151147142135
32°F199191186181177173168163154
28°F223217211207202199193188178
24°F251243237233228224219214207
20°F276268262257252247242237230
16°F300292286280275270264259251

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
5,868
Cooling degree days, base 65°F
699
Growing degree days, base 40°F
5,175
Growing degree days, base 45°F
3,994
Growing degree days, base 50°F
2,955
Growing degree days, base 55°F
2,056
Growing degree days, base 60°F
1,301

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14502
February96504
March837023
April4596115
May19841320
June38140552
July4238699
August10194649
September10370419
October4049144
November696023
December1,00904

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 9.5 km from Roaring Spring. 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 USC00360132 (Altoona 7 Sw). Public domain.