Spruce Pine Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Spruce Pine 2 Ne. 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 26 and the first fall freeze around October 20, a growing season of about 177 days.
- Median at 36°F
- last May 7, first October 9
- Median at 32°F
- last April 26, first October 20
- Median at 28°F
- last April 11, first October 29
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.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 23 | May 18 | May 13 | May 9 | May 7 | May 4 | May 1 | Apr 28 | Apr 22 |
| 32°F | May 13 | May 7 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 18 | Apr 15 | Apr 10 |
| 28°F | Apr 30 | Apr 21 | Apr 17 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 2 | Mar 28 |
| 24°F | Apr 13 | Apr 6 | Apr 3 | Mar 31 | Mar 28 | Mar 24 | Mar 20 | Mar 16 | Mar 9 |
| 20°F | Mar 31 | Mar 26 | Mar 20 | Mar 17 | Mar 14 | Mar 10 | Mar 5 | Feb 28 | Feb 21 |
| 16°F | Mar 20 | Mar 14 | Mar 10 | Mar 5 | Feb 28 | Feb 25 | Feb 19 | Feb 11 | Feb 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.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 14 | Oct 19 | Oct 25 |
| 32°F | Oct 6 | Oct 11 | Oct 14 | Oct 16 | Oct 20 | Oct 22 | Oct 25 | Oct 28 | Nov 2 |
| 28°F | Oct 15 | Oct 19 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 7 | Nov 12 |
| 24°F | Oct 25 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 19 | Nov 24 |
| 20°F | Nov 2 | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 23 | Nov 28 | Dec 2 | Dec 10 |
| 16°F | Nov 14 | Nov 21 | Nov 26 | Dec 1 | Dec 5 | Dec 10 | Dec 18 | Dec 25 | Jan 2 |
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.
| Threshold | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | 176 | 169 | 163 | 159 | 155 | 151 | 147 | 142 | 136 |
| 32°F | 197 | 191 | 185 | 181 | 177 | 173 | 168 | 162 | 156 |
| 28°F | 219 | 213 | 207 | 203 | 199 | 196 | 191 | 186 | 178 |
| 24°F | 250 | 241 | 235 | 229 | 225 | 220 | 216 | 210 | 203 |
| 20°F | 280 | 271 | 263 | 256 | 250 | 246 | 241 | 234 | 224 |
| 16°F | 313 | 302 | 293 | 286 | 280 | 275 | 267 | 260 | 250 |
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
- 4,997
- Cooling degree days, base 65°F
- 484
- Growing degree days, base 40°F
- 5,277
- Growing degree days, base 45°F
- 3,956
- Growing degree days, base 50°F
- 2,824
- Growing degree days, base 55°F
- 1,872
- Growing degree days, base 60°F
- 1,088
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 959 | 0 | 3 |
| February | 797 | 0 | 7 |
| March | 670 | 0 | 36 |
| April | 403 | 1 | 121 |
| May | 179 | 19 | 314 |
| June | 30 | 93 | 513 |
| July | 6 | 180 | 639 |
| August | 9 | 144 | 600 |
| September | 93 | 43 | 402 |
| October | 364 | 4 | 154 |
| November | 641 | 0 | 28 |
| December | 848 | 0 | 9 |
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 6 km from Spruce Pine. 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 USC00318221 (Spruce Pine 2 Ne). Public domain.