Piney Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Hot Springs 1 Nne. 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 19 and the first fall freeze around November 13, a growing season of about 239 days.
- Median at 36°F
- last April 2, first November 3
- Median at 32°F
- last March 19, first November 13
- Median at 28°F
- last March 6, first November 27
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 19 | Apr 12 | Apr 9 | Apr 6 | Apr 2 | Mar 31 | Mar 26 | Mar 22 | Mar 14 |
| 32°F | Apr 7 | Apr 2 | Mar 28 | Mar 23 | Mar 19 | Mar 15 | Mar 11 | Mar 6 | Mar 1 |
| 28°F | Mar 26 | Mar 18 | Mar 13 | Mar 9 | Mar 6 | Mar 2 | Feb 27 | Feb 21 | Feb 13 |
| 24°F | Mar 11 | Mar 5 | Mar 2 | Feb 26 | Feb 21 | Feb 16 | Feb 10 | Feb 3 | Jan 26 |
| 20°F | Mar 3 | Feb 24 | Feb 17 | Feb 10 | Feb 3 | Jan 31 | Jan 25 | Jan 18 | Jan 6 |
| 16°F | Feb 19 | Feb 10 | Feb 4 | Jan 31 | Jan 26 | Jan 20 | Jan 14 | Jan 7 | Dec 30 |
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 19 | Oct 24 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 9 | Nov 13 | Nov 19 |
| 32°F | Oct 28 | Nov 2 | Nov 6 | Nov 10 | Nov 13 | Nov 17 | Nov 22 | Nov 27 | Dec 3 |
| 28°F | Nov 7 | Nov 13 | Nov 18 | Nov 22 | Nov 27 | Nov 30 | Dec 4 | Dec 9 | Dec 18 |
| 24°F | Nov 17 | Nov 26 | Dec 1 | Dec 6 | Dec 12 | Dec 18 | Dec 23 | Dec 30 | Jan 7 |
| 20°F | Dec 2 | Dec 12 | Dec 21 | Dec 26 | Dec 31 | Jan 4 | Jan 9 | Jan 16 | Jan 29 |
| 16°F | Dec 14 | Dec 24 | Dec 31 | Jan 3 | Jan 8 | Jan 12 | Jan 17 | Jan 25 | Feb 4 |
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 | 239 | 230 | 225 | 221 | 215 | 211 | 206 | 200 | 192 |
| 32°F | 265 | 256 | 249 | 244 | 239 | 233 | 228 | 222 | 213 |
| 28°F | 292 | 282 | 277 | 271 | 266 | 260 | 254 | 246 | 236 |
| 24°F | 325 | 315 | 306 | 300 | 294 | 288 | 281 | 273 | 264 |
| 20°F | 358 | 346 | 337 | 330 | 323 | 317 | 307 | 301 | 291 |
| 16°F | 365 | 365 | 365 | 356 | 350 | 341 | 334 | 325 | 314 |
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
- 94% of years
- 16°F or colder
- 70% 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
- 2,983
- Cooling degree days, base 65°F
- 2,147
- Growing degree days, base 40°F
- 8,510
- Growing degree days, base 45°F
- 6,932
- Growing degree days, base 50°F
- 5,504
- Growing degree days, base 55°F
- 4,228
- Growing degree days, base 60°F
- 3,108
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 718 | 1 | 32 |
| February | 545 | 2 | 59 |
| March | 366 | 13 | 185 |
| April | 143 | 58 | 374 |
| May | 28 | 195 | 633 |
| June | 1 | 401 | 850 |
| July | 0 | 546 | 1,011 |
| August | 0 | 527 | 992 |
| September | 10 | 311 | 751 |
| October | 133 | 86 | 426 |
| November | 390 | 8 | 146 |
| December | 650 | 1 | 45 |
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 7.2 km from Piney. 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 USC00033466 (Hot Springs 1 Nne). Public domain.