Cornville Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Tuzigoot. 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 10, a growing season of about 223 days.
- Median at 36°F
- last April 17, first October 31
- Median at 32°F
- last March 30, first November 10
- Median at 28°F
- last March 5, first November 20
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 6 | Apr 30 | Apr 26 | Apr 22 | Apr 17 | Apr 13 | Apr 8 | Apr 4 | Mar 29 |
| 32°F | Apr 21 | Apr 11 | Apr 6 | Apr 2 | Mar 30 | Mar 25 | Mar 19 | Mar 15 | Mar 9 |
| 28°F | Mar 31 | Mar 18 | Mar 14 | Mar 9 | Mar 5 | Mar 2 | Feb 27 | Feb 22 | Feb 14 |
| 24°F | Mar 5 | Feb 27 | Feb 22 | Feb 18 | Feb 13 | Feb 8 | Feb 4 | Jan 29 | Jan 18 |
| 20°F | Feb 20 | Feb 12 | Feb 6 | Feb 1 | Jan 24 | Jan 17 | Jan 8 | Jan 1 | Dec 22 |
| 16°F | Feb 12 | Feb 2 | Jan 24 | Jan 13 | Jan 8 | Jan 4 | Jan 1 | Dec 25 | Dec 17 |
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 17 | Oct 21 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 |
| 32°F | Oct 25 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 23 |
| 28°F | Nov 5 | Nov 10 | Nov 15 | Nov 17 | Nov 20 | Nov 23 | Nov 27 | Dec 1 | Dec 5 |
| 24°F | Nov 17 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 6 | Dec 10 | Dec 14 | Dec 20 |
| 20°F | Nov 29 | Dec 4 | Dec 8 | Dec 12 | Dec 17 | Dec 23 | Dec 29 | Jan 5 | Jan 20 |
| 16°F | Dec 11 | Dec 18 | Dec 25 | Dec 31 | Jan 3 | Jan 7 | Jan 13 | Jan 29 | Feb 9 |
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 | 218 | 211 | 204 | 199 | 194 | 190 | 185 | 179 | 171 |
| 32°F | 248 | 239 | 234 | 229 | 223 | 219 | 214 | 209 | 199 |
| 28°F | 282 | 274 | 268 | 262 | 257 | 252 | 247 | 240 | 230 |
| 24°F | 320 | 309 | 302 | 296 | 290 | 285 | 280 | 273 | 262 |
| 20°F | 360 | 351 | 345 | 338 | 331 | 324 | 316 | 307 | 296 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 364 | 355 | 347 | 332 |
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
- 91% of years
- 16°F or colder
- 39% 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
- 2,657
- Cooling degree days, base 65°F
- 2,136
- Growing degree days, base 40°F
- 8,652
- Growing degree days, base 45°F
- 6,968
- Growing degree days, base 50°F
- 5,464
- Growing degree days, base 55°F
- 4,172
- Growing degree days, base 60°F
- 3,067
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 609 | 0 | 15 |
| February | 459 | 0 | 50 |
| March | 330 | 2 | 166 |
| April | 148 | 26 | 334 |
| May | 37 | 171 | 600 |
| June | 1 | 424 | 873 |
| July | 0 | 587 | 1,052 |
| August | 0 | 526 | 990 |
| September | 2 | 325 | 772 |
| October | 84 | 73 | 456 |
| November | 355 | 2 | 141 |
| December | 632 | 0 | 13 |
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 11.3 km from Cornville. 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 USC00028904 (Tuzigoot). Public domain.