Falkner Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Ripley. 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 3 and the first fall freeze around October 30, a growing season of about 210 days.
- Median at 36°F
- last April 14, first October 22
- Median at 32°F
- last April 3, first October 30
- Median at 28°F
- last March 21, first November 10
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 30 | Apr 24 | Apr 21 | Apr 18 | Apr 14 | Apr 12 | Apr 9 | Apr 5 | Mar 31 |
| 32°F | Apr 19 | Apr 14 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 26 | Mar 22 | Mar 15 |
| 28°F | Apr 9 | Apr 3 | Mar 30 | Mar 25 | Mar 21 | Mar 17 | Mar 13 | Mar 7 | Mar 1 |
| 24°F | Mar 27 | Mar 20 | Mar 15 | Mar 10 | Mar 5 | Mar 2 | Feb 27 | Feb 22 | Feb 15 |
| 20°F | Mar 12 | Mar 5 | Mar 1 | Feb 26 | Feb 21 | Feb 15 | Feb 9 | Feb 2 | Jan 26 |
| 16°F | Mar 2 | Feb 23 | Feb 14 | Feb 7 | Feb 2 | Jan 30 | Jan 24 | Jan 16 | Jan 5 |
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 12 | Oct 15 | Oct 18 | Oct 20 | Oct 22 | Oct 25 | Oct 26 | Oct 29 | Nov 1 |
| 32°F | Oct 19 | Oct 23 | Oct 26 | Oct 28 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 14 |
| 28°F | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 10 | Nov 13 | Nov 17 | Nov 22 | Nov 29 |
| 24°F | Nov 6 | Nov 11 | Nov 16 | Nov 19 | Nov 24 | Nov 29 | Dec 2 | Dec 7 | Dec 19 |
| 20°F | Nov 18 | Nov 26 | Dec 1 | Dec 5 | Dec 10 | Dec 18 | Dec 24 | Jan 1 | Jan 10 |
| 16°F | Dec 1 | Dec 11 | Dec 21 | Dec 27 | Jan 1 | Jan 5 | Jan 10 | Jan 16 | Jan 28 |
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 | 208 | 203 | 198 | 194 | 190 | 187 | 183 | 178 | 173 |
| 32°F | 234 | 226 | 219 | 215 | 210 | 206 | 202 | 197 | 190 |
| 28°F | 262 | 252 | 246 | 240 | 235 | 231 | 226 | 218 | 209 |
| 24°F | 293 | 281 | 274 | 268 | 262 | 256 | 249 | 242 | 233 |
| 20°F | 329 | 316 | 307 | 301 | 295 | 287 | 279 | 272 | 259 |
| 16°F | 359 | 347 | 340 | 333 | 327 | 319 | 311 | 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
- 100% of years
- 16°F or colder
- 92% 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
- 3,541
- Cooling degree days, base 65°F
- 1,662
- Growing degree days, base 40°F
- 7,607
- Growing degree days, base 45°F
- 6,121
- Growing degree days, base 50°F
- 4,780
- Growing degree days, base 55°F
- 3,587
- Growing degree days, base 60°F
- 2,547
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 808 | 0 | 28 |
| February | 626 | 1 | 38 |
| March | 448 | 8 | 137 |
| April | 205 | 40 | 308 |
| May | 46 | 149 | 567 |
| June | 2 | 327 | 775 |
| July | 0 | 442 | 907 |
| August | 0 | 416 | 880 |
| September | 18 | 226 | 658 |
| October | 199 | 48 | 335 |
| November | 477 | 5 | 108 |
| December | 712 | 1 | 38 |
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 11.5 km from Falkner. 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 USC00227467 (Ripley). Public domain.