Tyrone climate

Tyrone Frost Dates and Growing Season

NOAA 1991-2020 normals for White Signal, 17.4 km from Tyrone, elevation 5991 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for White Signal. 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 23 and the first fall freeze around October 26, a growing season of about 185 days.

Median at 36°F
last May 5, first October 18
Median at 32°F
last April 23, first October 26
Median at 28°F
last April 6, first November 4

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 24Apr 19
32°FMay 10May 4May 1Apr 27Apr 23Apr 19Apr 15Apr 10Apr 4
28°FApr 29Apr 21Apr 15Apr 10Apr 6Apr 2Mar 29Mar 26Mar 19
24°FApr 12Apr 3Mar 30Mar 25Mar 20Mar 16Mar 11Mar 4Feb 25
20°FMar 19Mar 12Mar 7Mar 3Feb 27Feb 22Feb 16Feb 8Jan 29
16°FMar 6Feb 27Feb 18Feb 12Feb 5Jan 30Jan 23Jan 13Dec 31

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°FOct 5Oct 9Oct 13Oct 15Oct 18Oct 20Oct 22Oct 25Oct 29
32°FOct 13Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 4Nov 8
28°FOct 19Oct 24Oct 28Nov 1Nov 4Nov 7Nov 11Nov 15Nov 19
24°FOct 28Nov 3Nov 7Nov 11Nov 15Nov 18Nov 22Nov 26Dec 1
20°FNov 7Nov 15Nov 19Nov 23Nov 27Nov 30Dec 3Dec 8Dec 15
16°FNov 17Nov 26Nov 30Dec 5Dec 9Dec 14Dec 20Dec 26Jan 7

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°F183177172168164160155150141
32°F207199194189185180176170161
28°F234226220215211206200193183
24°F269259251245240234227219209
20°F307295286279272266260252242
16°F344332323314307299291281271

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
99% 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
3,982
Cooling degree days, base 65°F
987
Growing degree days, base 40°F
6,371
Growing degree days, base 45°F
4,905
Growing degree days, base 50°F
3,654
Growing degree days, base 55°F
2,593
Growing degree days, base 60°F
1,706

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January78602
February62209
March523054
April2985180
May10566428
June6256700
July1306770
August2242705
September41102512
October2439248
November555043
December80303

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 17.4 km from Tyrone. 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 USC00299691 (White Signal). Public domain.