Radium Springs Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Jornada Exp Range. 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 27 and the first fall freeze around October 23, a growing season of about 178 days.
- Median at 36°F
- last May 7, first October 15
- Median at 32°F
- last April 27, first October 23
- Median at 28°F
- last April 13, first November 1
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 21 | May 16 | May 13 | May 10 | May 7 | May 5 | May 2 | Apr 30 | Apr 26 |
| 32°F | May 9 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 25 | Apr 21 | Apr 18 | Apr 13 |
| 28°F | Apr 29 | Apr 24 | Apr 20 | Apr 16 | Apr 13 | Apr 10 | Apr 6 | Apr 2 | Mar 28 |
| 24°F | Apr 14 | Apr 8 | Apr 5 | Apr 1 | Mar 28 | Mar 24 | Mar 20 | Mar 15 | Mar 7 |
| 20°F | Apr 2 | Mar 25 | Mar 18 | Mar 14 | Mar 9 | Mar 5 | Mar 2 | Feb 27 | Feb 19 |
| 16°F | Mar 13 | Mar 6 | Mar 1 | Feb 26 | Feb 21 | Feb 16 | Feb 11 | Feb 5 | Jan 28 |
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 3 | Oct 6 | Oct 10 | Oct 13 | Oct 15 | Oct 17 | Oct 19 | Oct 22 | Oct 27 |
| 32°F | Oct 10 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 26 | Oct 28 | Nov 1 | Nov 5 |
| 28°F | Oct 16 | Oct 20 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 9 | Nov 13 |
| 24°F | Oct 23 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 14 | Nov 18 | Nov 24 |
| 20°F | Nov 4 | Nov 9 | Nov 13 | Nov 15 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 3 |
| 16°F | Nov 11 | Nov 17 | Nov 22 | Nov 26 | Nov 30 | Dec 2 | Dec 5 | Dec 9 | Dec 16 |
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 | 176 | 170 | 166 | 163 | 159 | 156 | 153 | 148 | 142 |
| 32°F | 196 | 190 | 185 | 182 | 178 | 175 | 171 | 166 | 160 |
| 28°F | 220 | 213 | 207 | 203 | 199 | 195 | 191 | 186 | 178 |
| 24°F | 248 | 239 | 233 | 227 | 223 | 219 | 214 | 209 | 201 |
| 20°F | 277 | 268 | 262 | 257 | 251 | 246 | 240 | 232 | 223 |
| 16°F | 309 | 298 | 291 | 285 | 280 | 274 | 269 | 263 | 254 |
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
- 3,569
- Cooling degree days, base 65°F
- 1,588
- Growing degree days, base 40°F
- 7,383
- Growing degree days, base 45°F
- 5,882
- Growing degree days, base 50°F
- 4,558
- Growing degree days, base 55°F
- 3,406
- Growing degree days, base 60°F
- 2,417
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 790 | 0 | 4 |
| February | 576 | 1 | 27 |
| March | 437 | 1 | 102 |
| April | 222 | 11 | 252 |
| May | 54 | 110 | 522 |
| June | 2 | 348 | 796 |
| July | 0 | 473 | 938 |
| August | 0 | 408 | 873 |
| September | 12 | 210 | 648 |
| October | 174 | 27 | 328 |
| November | 511 | 1 | 63 |
| December | 792 | 0 | 6 |
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 21.8 km from Radium Springs. 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 USC00294426 (Jornada Exp Range). Public domain.