Summerfield Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Piedmont Triad Intl 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 March 30 and the first fall freeze around November 5, a growing season of about 220 days.
- Median at 36°F
- last April 13, first October 27
- Median at 32°F
- last March 30, first November 5
- Median at 28°F
- last March 18, first November 17
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 | Apr 27 | Apr 22 | Apr 18 | Apr 15 | Apr 13 | Apr 9 | Apr 6 | Apr 3 | Mar 29 |
| 32°F | Apr 14 | Apr 8 | Apr 5 | Apr 2 | Mar 30 | Mar 27 | Mar 24 | Mar 19 | Mar 12 |
| 28°F | Apr 4 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 15 | Mar 11 | Mar 7 | Feb 28 |
| 24°F | Mar 25 | Mar 19 | Mar 15 | Mar 10 | Mar 4 | Feb 28 | Feb 25 | Feb 19 | Feb 10 |
| 20°F | Mar 15 | Mar 7 | Mar 1 | Feb 25 | Feb 19 | Feb 12 | Feb 6 | Feb 1 | Jan 23 |
| 16°F | Mar 6 | Feb 25 | Feb 14 | Feb 6 | Feb 1 | Jan 29 | Jan 24 | Jan 17 | Jan 8 |
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 | Oct 14 | Oct 18 | Oct 22 | Oct 25 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 7 |
| 32°F | Oct 25 | Oct 30 | Nov 1 | Nov 3 | Nov 5 | Nov 7 | Nov 11 | Nov 14 | Nov 21 |
| 28°F | Nov 3 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 4 |
| 24°F | Nov 13 | Nov 18 | Nov 23 | Nov 28 | Dec 2 | Dec 5 | Dec 10 | Dec 18 | Dec 26 |
| 20°F | Nov 27 | Dec 3 | Dec 8 | Dec 14 | Dec 20 | Dec 26 | Dec 31 | Jan 7 | Jan 17 |
| 16°F | Dec 10 | Dec 19 | Dec 28 | Jan 1 | Jan 7 | Jan 13 | Jan 17 | Jan 24 | Feb 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 | 217 | 211 | 206 | 201 | 198 | 194 | 190 | 185 | 177 |
| 32°F | 243 | 235 | 229 | 225 | 220 | 216 | 212 | 208 | 201 |
| 28°F | 270 | 260 | 253 | 248 | 244 | 239 | 234 | 229 | 222 |
| 24°F | 299 | 289 | 282 | 276 | 270 | 265 | 259 | 252 | 243 |
| 20°F | 332 | 323 | 315 | 307 | 301 | 296 | 288 | 280 | 269 |
| 16°F | 365 | 354 | 345 | 336 | 331 | 325 | 317 | 305 | 294 |
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
- 99% of years
- 16°F or colder
- 88% 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
- 3,500
- Cooling degree days, base 65°F
- 1,552
- Growing degree days, base 40°F
- 7,471
- Growing degree days, base 45°F
- 5,967
- Growing degree days, base 50°F
- 4,622
- Growing degree days, base 55°F
- 3,435
- Growing degree days, base 60°F
- 2,415
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 784 | 0 | 22 |
| February | 617 | 1 | 34 |
| March | 462 | 6 | 125 |
| April | 204 | 38 | 301 |
| May | 59 | 138 | 545 |
| June | 5 | 314 | 759 |
| July | 0 | 431 | 896 |
| August | 0 | 382 | 846 |
| September | 22 | 200 | 629 |
| October | 187 | 39 | 327 |
| November | 461 | 3 | 103 |
| December | 699 | 1 | 36 |
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 12.9 km from Summerfield. 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 USW00013723 (Piedmont Triad Intl AP). Public domain.