Redkey Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Farmland 5 Nnw. 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 25 and the first fall freeze around October 16, a growing season of about 173 days.
- Median at 36°F
- last May 5, first October 5
- Median at 32°F
- last April 25, first October 16
- Median at 28°F
- last April 14, first October 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 | May 22 | May 16 | May 11 | May 8 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 21 |
| 32°F | May 11 | May 5 | May 1 | Apr 28 | Apr 25 | Apr 23 | Apr 20 | Apr 17 | Apr 11 |
| 28°F | Apr 29 | Apr 24 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 | Apr 4 | Mar 31 |
| 24°F | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 30 | Mar 27 | Mar 23 | Mar 18 |
| 20°F | Apr 6 | Apr 1 | Mar 29 | Mar 26 | Mar 22 | Mar 19 | Mar 16 | Mar 12 | Mar 6 |
| 16°F | Mar 28 | Mar 22 | Mar 18 | Mar 14 | Mar 12 | Mar 8 | Mar 5 | Mar 1 | Feb 21 |
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 | Sep 22 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 13 | Oct 18 |
| 32°F | Oct 1 | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 18 | Oct 21 | Oct 24 | Oct 29 |
| 28°F | Oct 13 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 10 |
| 24°F | Oct 24 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 19 | Nov 26 |
| 20°F | Nov 5 | Nov 9 | Nov 14 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 8 |
| 16°F | Nov 14 | Nov 21 | Nov 27 | Nov 30 | Dec 3 | Dec 6 | Dec 10 | Dec 16 | Dec 23 |
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 | 171 | 163 | 158 | 155 | 151 | 146 | 141 | 136 | 131 |
| 32°F | 191 | 185 | 181 | 176 | 173 | 169 | 163 | 158 | 151 |
| 28°F | 216 | 208 | 203 | 199 | 195 | 191 | 186 | 181 | 175 |
| 24°F | 242 | 234 | 229 | 223 | 219 | 214 | 210 | 204 | 197 |
| 20°F | 268 | 259 | 252 | 247 | 242 | 237 | 233 | 227 | 220 |
| 16°F | 289 | 281 | 275 | 270 | 265 | 260 | 254 | 247 | 240 |
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
- 100% 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
- 5,878
- Cooling degree days, base 65°F
- 875
- Growing degree days, base 40°F
- 5,496
- Growing degree days, base 45°F
- 4,304
- Growing degree days, base 50°F
- 3,247
- Growing degree days, base 55°F
- 2,319
- Growing degree days, base 60°F
- 1,528
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,207 | 0 | 3 |
| February | 1,004 | 0 | 4 |
| March | 814 | 1 | 34 |
| April | 439 | 9 | 131 |
| May | 172 | 70 | 374 |
| June | 25 | 198 | 622 |
| July | 5 | 267 | 727 |
| August | 10 | 217 | 671 |
| September | 93 | 99 | 459 |
| October | 370 | 15 | 179 |
| November | 698 | 1 | 38 |
| December | 1,040 | 0 | 5 |
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 10.6 km from Redkey. 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 USC00122825 (Farmland 5 Nnw). Public domain.