Coker Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Tuscaloosa Acfd. 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 12 and the first fall freeze around November 15, a growing season of about 250 days.
- Median at 36°F
- last March 28, first November 4
- Median at 32°F
- last March 12, first November 15
- Median at 28°F
- last February 28, first December 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 | Apr 15 | Apr 8 | Apr 4 | Apr 1 | Mar 28 | Mar 24 | Mar 19 | Mar 14 | Mar 6 |
| 32°F | Apr 2 | Mar 26 | Mar 21 | Mar 17 | Mar 12 | Mar 8 | Mar 3 | Feb 27 | Feb 22 |
| 28°F | Mar 18 | Mar 11 | Mar 7 | Mar 3 | Feb 28 | Feb 23 | Feb 19 | Feb 13 | Feb 2 |
| 24°F | Mar 8 | Mar 1 | Feb 25 | Feb 18 | Feb 11 | Feb 5 | Jan 31 | Jan 24 | Jan 12 |
| 20°F | Feb 27 | Feb 13 | Feb 6 | Feb 1 | Jan 29 | Jan 23 | Jan 16 | Jan 9 | Dec 31 |
| 16°F | Feb 10 | Feb 3 | Jan 31 | Jan 26 | Jan 20 | Jan 15 | Jan 11 | 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 24 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 13 | Nov 19 |
| 32°F | Nov 2 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 29 | Dec 4 |
| 28°F | Nov 11 | Nov 17 | Nov 22 | Nov 26 | Dec 1 | Dec 4 | Dec 8 | Dec 19 | Dec 30 |
| 24°F | Nov 24 | Dec 1 | Dec 6 | Dec 14 | Dec 22 | Dec 29 | Jan 2 | Jan 8 | Jan 18 |
| 20°F | Dec 7 | Dec 20 | Dec 27 | Jan 1 | Jan 3 | Jan 8 | Jan 14 | Jan 21 | Feb 3 |
| 16°F | Dec 22 | Dec 31 | Jan 3 | Jan 7 | Jan 11 | Jan 16 | Jan 20 | Jan 29 | Feb 5 |
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 | 247 | 238 | 232 | 227 | 222 | 217 | 213 | 207 | 200 |
| 32°F | 276 | 267 | 260 | 255 | 250 | 245 | 239 | 232 | 223 |
| 28°F | 308 | 297 | 290 | 283 | 277 | 272 | 266 | 260 | 249 |
| 24°F | 342 | 333 | 324 | 317 | 310 | 304 | 297 | 289 | 279 |
| 20°F | 365 | 365 | 355 | 347 | 338 | 333 | 326 | 318 | 305 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 359 | 348 | 337 | 326 |
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
- 98% of years
- 20°F or colder
- 78% of years
- 16°F or colder
- 46% 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
- 2,149
- Cooling degree days, base 65°F
- 2,554
- Growing degree days, base 40°F
- 9,612
- Growing degree days, base 45°F
- 7,918
- Growing degree days, base 50°F
- 6,349
- Growing degree days, base 55°F
- 4,923
- Growing degree days, base 60°F
- 3,653
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 565 | 3 | 85 |
| February | 399 | 8 | 121 |
| March | 229 | 34 | 295 |
| April | 74 | 100 | 477 |
| May | 10 | 282 | 736 |
| June | 0 | 465 | 915 |
| July | 0 | 569 | 1,034 |
| August | 0 | 552 | 1,017 |
| September | 2 | 384 | 832 |
| October | 77 | 135 | 524 |
| November | 294 | 18 | 208 |
| December | 498 | 5 | 105 |
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 7.7 km from Coker. 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 USC00018380 (Tuscaloosa Acfd). Public domain.