Seth Ward Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Plainview. 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 6 and the first fall freeze around November 2, a growing season of about 209 days.
- Median at 36°F
- last April 17, first October 23
- Median at 32°F
- last April 6, first November 2
- Median at 28°F
- last March 25, first November 12
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 2 | Apr 27 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 | Apr 2 |
| 32°F | Apr 23 | Apr 18 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 26 | Mar 19 |
| 28°F | Apr 13 | Apr 7 | Apr 2 | Mar 30 | Mar 25 | Mar 20 | Mar 16 | Mar 11 | Mar 5 |
| 24°F | Apr 1 | Mar 25 | Mar 20 | Mar 15 | Mar 11 | Mar 7 | Mar 4 | Mar 1 | Feb 22 |
| 20°F | Mar 19 | Mar 12 | Mar 7 | Mar 3 | Mar 1 | Feb 25 | Feb 21 | Feb 15 | Feb 5 |
| 16°F | Mar 6 | Mar 2 | Feb 25 | Feb 20 | Feb 14 | Feb 8 | Feb 1 | Jan 24 | Jan 10 |
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 10 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 28 | Nov 1 | Nov 4 |
| 32°F | Oct 19 | Oct 25 | Oct 28 | Nov 1 | Nov 2 | Nov 5 | Nov 7 | Nov 10 | Nov 16 |
| 28°F | Oct 30 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 14 | Nov 18 | Nov 22 | Nov 26 |
| 24°F | Nov 6 | Nov 12 | Nov 15 | Nov 19 | Nov 22 | Nov 25 | Nov 29 | Dec 3 | Dec 9 |
| 20°F | Nov 14 | Nov 21 | Nov 25 | Nov 29 | Dec 3 | Dec 7 | Dec 11 | Dec 17 | Dec 24 |
| 16°F | Nov 24 | Nov 30 | Dec 5 | Dec 10 | Dec 16 | Dec 23 | Dec 29 | Jan 5 | Jan 15 |
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 | 208 | 201 | 196 | 192 | 188 | 184 | 180 | 175 | 169 |
| 32°F | 230 | 223 | 217 | 213 | 209 | 204 | 200 | 195 | 188 |
| 28°F | 256 | 246 | 240 | 236 | 230 | 225 | 220 | 214 | 206 |
| 24°F | 279 | 270 | 264 | 260 | 254 | 248 | 243 | 237 | 228 |
| 20°F | 307 | 299 | 292 | 286 | 280 | 275 | 268 | 262 | 253 |
| 16°F | 346 | 332 | 323 | 315 | 308 | 302 | 295 | 287 | 276 |
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
- 98% 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
- 3,640
- Cooling degree days, base 65°F
- 1,723
- Growing degree days, base 40°F
- 7,601
- Growing degree days, base 45°F
- 6,108
- Growing degree days, base 50°F
- 4,769
- Growing degree days, base 55°F
- 3,594
- Growing degree days, base 60°F
- 2,582
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 800 | 0 | 13 |
| February | 622 | 0 | 36 |
| March | 449 | 5 | 130 |
| April | 222 | 32 | 288 |
| May | 63 | 164 | 568 |
| June | 2 | 366 | 814 |
| July | 0 | 470 | 935 |
| August | 1 | 424 | 888 |
| September | 27 | 216 | 640 |
| October | 189 | 45 | 345 |
| November | 498 | 2 | 94 |
| December | 769 | 0 | 18 |
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 2.8 km from Seth Ward. 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 USC00417079 (Plainview). Public domain.