Springtown Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Ft Worth Nature Ctr. 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 13 and the first fall freeze around November 20, a growing season of about 253 days.
- Median at 36°F
- last March 28, first November 8
- Median at 32°F
- last March 13, first November 20
- Median at 28°F
- last February 28, first December 2
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 16 | Apr 8 | Apr 4 | Mar 31 | Mar 28 | Mar 23 | Mar 18 | Mar 13 | Mar 5 |
| 32°F | Apr 2 | Mar 28 | Mar 22 | Mar 17 | Mar 13 | Mar 9 | Mar 4 | Feb 28 | Feb 21 |
| 28°F | Mar 22 | Mar 14 | Mar 9 | Mar 4 | Feb 28 | Feb 24 | Feb 18 | Feb 10 | Jan 31 |
| 24°F | Mar 9 | Mar 2 | Feb 26 | Feb 18 | Feb 12 | Feb 5 | Jan 30 | Jan 24 | Jan 13 |
| 20°F | Mar 1 | Feb 17 | Feb 8 | Feb 1 | Jan 27 | Jan 21 | Jan 14 | Jan 6 | Dec 26 |
| 16°F | Feb 11 | Feb 5 | Jan 30 | Jan 24 | Jan 18 | Jan 10 | Jan 5 | Dec 31 | Dec 20 |
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 23 | Oct 29 | Nov 1 | Nov 4 | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 26 |
| 32°F | Nov 2 | Nov 7 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 29 | Dec 3 | Dec 9 |
| 28°F | Nov 11 | Nov 18 | Nov 23 | Nov 28 | Dec 2 | Dec 6 | Dec 12 | Dec 17 | Dec 24 |
| 24°F | Nov 24 | Dec 1 | Dec 7 | Dec 12 | Dec 19 | Dec 25 | Dec 31 | Jan 5 | Jan 17 |
| 20°F | Dec 4 | Dec 12 | Dec 19 | Dec 26 | Dec 31 | Jan 5 | Jan 11 | Jan 19 | Feb 1 |
| 16°F | Dec 12 | Dec 22 | Dec 31 | Jan 3 | Jan 7 | Jan 14 | Jan 19 | 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 | 254 | 246 | 239 | 233 | 228 | 222 | 217 | 210 | 201 |
| 32°F | 280 | 270 | 264 | 258 | 253 | 247 | 241 | 235 | 225 |
| 28°F | 311 | 300 | 292 | 285 | 279 | 273 | 267 | 258 | 249 |
| 24°F | 346 | 335 | 327 | 319 | 312 | 305 | 298 | 288 | 276 |
| 20°F | 365 | 365 | 359 | 351 | 344 | 336 | 329 | 320 | 305 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 357 | 347 | 334 |
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
- 79% of years
- 16°F or colder
- 42% 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
- 2,352
- Cooling degree days, base 65°F
- 2,755
- Growing degree days, base 40°F
- 9,666
- Growing degree days, base 45°F
- 8,008
- Growing degree days, base 50°F
- 6,470
- Growing degree days, base 55°F
- 5,077
- Growing degree days, base 60°F
- 3,836
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 608 | 2 | 62 |
| February | 439 | 7 | 115 |
| March | 268 | 28 | 267 |
| April | 99 | 94 | 452 |
| May | 16 | 274 | 724 |
| June | 0 | 492 | 942 |
| July | 0 | 645 | 1,110 |
| August | 0 | 635 | 1,100 |
| September | 4 | 400 | 846 |
| October | 88 | 148 | 530 |
| November | 290 | 26 | 237 |
| December | 542 | 4 | 87 |
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 23.5 km from Springtown. 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 USC00413289 (Ft Worth Nature Ctr). Public domain.