Metcalfe Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Greenville Asos. 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 12 and the first fall freeze around November 13, a growing season of about 247 days.
- Median at 36°F
- last March 25, first November 1
- Median at 32°F
- last March 12, first November 13
- Median at 28°F
- last February 27, first November 26
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 10 | Apr 4 | Apr 1 | Mar 29 | Mar 25 | Mar 20 | Mar 16 | Mar 12 | Mar 5 |
| 32°F | Mar 30 | Mar 24 | Mar 20 | Mar 15 | Mar 12 | Mar 8 | Mar 3 | Feb 27 | Feb 21 |
| 28°F | Mar 17 | Mar 11 | Mar 6 | Mar 2 | Feb 27 | Feb 22 | Feb 18 | Feb 10 | Jan 31 |
| 24°F | Mar 6 | Feb 27 | Feb 20 | Feb 14 | Feb 7 | Feb 1 | Jan 29 | Jan 20 | Jan 7 |
| 20°F | Feb 17 | Feb 8 | Feb 1 | Jan 29 | Jan 23 | Jan 18 | Jan 11 | Jan 3 | Dec 25 |
| 16°F | Feb 9 | Jan 31 | Jan 27 | Jan 21 | Jan 17 | Jan 11 | Jan 5 | Dec 31 | Dec 23 |
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 20 | Oct 24 | Oct 27 | Oct 31 | Nov 1 | Nov 5 | Nov 7 | Nov 11 | Nov 18 |
| 32°F | Oct 30 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Dec 1 |
| 28°F | Nov 7 | Nov 12 | Nov 17 | Nov 21 | Nov 26 | Nov 30 | Dec 4 | Dec 9 | Dec 21 |
| 24°F | Nov 18 | Nov 27 | Dec 2 | Dec 8 | Dec 15 | Dec 24 | Dec 31 | Jan 5 | Jan 16 |
| 20°F | Dec 2 | Dec 12 | Dec 22 | Dec 29 | Jan 1 | Jan 6 | Jan 12 | Jan 19 | Feb 1 |
| 16°F | Dec 15 | Dec 26 | Jan 1 | Jan 4 | Jan 9 | Jan 12 | Jan 19 | Jan 24 | Feb 3 |
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 | 246 | 237 | 232 | 227 | 222 | 218 | 213 | 207 | 199 |
| 32°F | 272 | 264 | 257 | 251 | 247 | 242 | 237 | 231 | 223 |
| 28°F | 305 | 294 | 285 | 279 | 273 | 268 | 262 | 256 | 245 |
| 24°F | 347 | 333 | 324 | 316 | 308 | 301 | 294 | 285 | 274 |
| 20°F | 365 | 365 | 360 | 351 | 344 | 337 | 331 | 322 | 311 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 359 | 347 | 334 |
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
- 97% of years
- 20°F or colder
- 74% of years
- 16°F or colder
- 37% 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
- 2,619
- Cooling degree days, base 65°F
- 2,295
- Growing degree days, base 40°F
- 8,954
- Growing degree days, base 45°F
- 7,340
- Growing degree days, base 50°F
- 5,858
- Growing degree days, base 55°F
- 4,514
- Growing degree days, base 60°F
- 3,324
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 651 | 2 | 59 |
| February | 484 | 5 | 86 |
| March | 311 | 20 | 224 |
| April | 105 | 76 | 424 |
| May | 15 | 249 | 699 |
| June | 0 | 431 | 880 |
| July | 0 | 541 | 1,006 |
| August | 0 | 515 | 980 |
| September | 4 | 334 | 780 |
| October | 104 | 107 | 471 |
| November | 357 | 14 | 173 |
| December | 588 | 4 | 77 |
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 3.8 km from Metcalfe. 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 USW00013939 (Greenville Asos). Public domain.