Doyle Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Sparta Wastewater Plant. 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 15 and the first fall freeze around October 23, a growing season of about 191 days.
- Median at 36°F
- last April 26, first October 15
- Median at 32°F
- last April 15, first October 23
- Median at 28°F
- last April 3, 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 11 | May 6 | May 2 | Apr 29 | Apr 26 | Apr 23 | Apr 20 | Apr 16 | Apr 10 |
| 32°F | Apr 30 | Apr 25 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 8 | Apr 5 | Mar 31 |
| 28°F | Apr 18 | Apr 13 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 28 | Mar 24 | Mar 17 |
| 24°F | Apr 7 | Apr 3 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 14 | Mar 8 | Mar 1 |
| 20°F | Mar 27 | Mar 21 | Mar 17 | Mar 12 | Mar 8 | Mar 3 | Feb 28 | Feb 23 | Feb 12 |
| 16°F | Mar 18 | Mar 11 | Mar 4 | Feb 28 | Feb 24 | Feb 18 | Feb 11 | Feb 4 | 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 5 | Oct 8 | Oct 11 | Oct 13 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 27 |
| 32°F | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 28 | Nov 1 | Nov 5 |
| 28°F | Oct 19 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 15 |
| 24°F | Oct 28 | Nov 2 | Nov 6 | Nov 9 | Nov 13 | Nov 15 | Nov 18 | Nov 23 | Nov 29 |
| 20°F | Nov 8 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Nov 29 | Dec 3 | Dec 7 | Dec 17 |
| 16°F | Nov 18 | Nov 27 | Dec 2 | Dec 6 | Dec 12 | Dec 19 | Dec 25 | Jan 1 | Jan 9 |
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 | 190 | 183 | 178 | 175 | 171 | 167 | 163 | 159 | 152 |
| 32°F | 212 | 205 | 200 | 195 | 191 | 188 | 184 | 179 | 172 |
| 28°F | 235 | 226 | 220 | 216 | 212 | 208 | 204 | 199 | 191 |
| 24°F | 261 | 251 | 244 | 239 | 234 | 229 | 224 | 219 | 212 |
| 20°F | 293 | 282 | 275 | 268 | 262 | 256 | 250 | 244 | 236 |
| 16°F | 326 | 315 | 307 | 301 | 293 | 287 | 280 | 271 | 260 |
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
- 3,879
- Cooling degree days, base 65°F
- 1,370
- Growing degree days, base 40°F
- 7,083
- Growing degree days, base 45°F
- 5,632
- Growing degree days, base 50°F
- 4,332
- Growing degree days, base 55°F
- 3,190
- Growing degree days, base 60°F
- 2,206
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 851 | 0 | 21 |
| February | 675 | 0 | 29 |
| March | 509 | 4 | 105 |
| April | 245 | 26 | 264 |
| May | 74 | 111 | 504 |
| June | 4 | 273 | 718 |
| July | 0 | 381 | 846 |
| August | 0 | 351 | 815 |
| September | 28 | 188 | 611 |
| October | 225 | 33 | 298 |
| November | 517 | 3 | 88 |
| December | 750 | 0 | 33 |
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 6.8 km from Doyle. 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 USC00408522 (Sparta Wastewater Plant). Public domain.