Landmark Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Little Rock AP Adams Fld. 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 21 and the first fall freeze around November 10, a growing season of about 234 days.
- Median at 36°F
- last April 3, first October 31
- Median at 32°F
- last March 21, first November 10
- Median at 28°F
- last March 8, first November 21
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 21 | Apr 13 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 27 | Mar 23 | Mar 16 |
| 32°F | Apr 6 | Apr 1 | Mar 28 | Mar 25 | Mar 21 | Mar 16 | Mar 13 | Mar 8 | Mar 2 |
| 28°F | Mar 26 | Mar 19 | Mar 15 | Mar 12 | Mar 8 | Mar 4 | Mar 1 | Feb 26 | Feb 20 |
| 24°F | Mar 15 | Mar 10 | Mar 5 | Mar 1 | Feb 26 | Feb 22 | Feb 18 | Feb 12 | Feb 1 |
| 20°F | Mar 7 | Feb 28 | Feb 21 | Feb 15 | Feb 10 | Feb 4 | Jan 30 | Jan 24 | Jan 14 |
| 16°F | Feb 22 | Feb 10 | Feb 4 | Jan 31 | Jan 27 | Jan 21 | Jan 14 | Jan 6 | Dec 30 |
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 23 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 14 |
| 32°F | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 20 | Nov 25 |
| 28°F | Nov 6 | Nov 10 | Nov 15 | Nov 18 | Nov 21 | Nov 24 | Nov 28 | Dec 2 | Dec 8 |
| 24°F | Nov 15 | Nov 21 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 12 | Dec 19 | Dec 27 |
| 20°F | Nov 29 | Dec 5 | Dec 11 | Dec 17 | Dec 22 | Dec 28 | Jan 1 | Jan 6 | Jan 16 |
| 16°F | Dec 10 | Dec 19 | Dec 27 | Jan 1 | Jan 3 | Jan 8 | Jan 15 | Jan 21 | Feb 2 |
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 | 234 | 226 | 220 | 216 | 211 | 206 | 202 | 197 | 190 |
| 32°F | 257 | 249 | 244 | 240 | 234 | 230 | 225 | 219 | 210 |
| 28°F | 281 | 273 | 267 | 261 | 256 | 252 | 247 | 241 | 233 |
| 24°F | 310 | 301 | 294 | 288 | 283 | 278 | 271 | 264 | 255 |
| 20°F | 344 | 335 | 328 | 321 | 315 | 307 | 301 | 294 | 283 |
| 16°F | 365 | 365 | 357 | 349 | 342 | 335 | 329 | 320 | 308 |
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
- 98% of years
- 16°F or colder
- 81% 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
- 3,165
- Cooling degree days, base 65°F
- 1,989
- Growing degree days, base 40°F
- 8,209
- Growing degree days, base 45°F
- 6,660
- Growing degree days, base 50°F
- 5,263
- Growing degree days, base 55°F
- 4,019
- Growing degree days, base 60°F
- 2,925
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 754 | 1 | 29 |
| February | 569 | 1 | 51 |
| March | 391 | 11 | 164 |
| April | 154 | 48 | 352 |
| May | 30 | 182 | 617 |
| June | 0 | 389 | 838 |
| July | 0 | 510 | 975 |
| August | 0 | 490 | 955 |
| September | 11 | 281 | 720 |
| October | 145 | 69 | 397 |
| November | 425 | 7 | 125 |
| December | 684 | 1 | 41 |
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 14.9 km from Landmark. 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 USW00013963 (Little Rock AP Adams Fld). Public domain.