Doyle Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Doyle 4 Sse. 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 May 21 and the first fall freeze around October 1, a growing season of about 130 days.
- Median at 36°F
- last June 10, first September 12
- Median at 32°F
- last May 21, first October 1
- Median at 28°F
- last May 2, first October 17
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 | Jun 29 | Jun 22 | Jun 16 | Jun 13 | Jun 10 | Jun 6 | Jun 3 | May 31 | May 23 |
| 32°F | Jun 11 | Jun 5 | May 31 | May 25 | May 21 | May 16 | May 11 | May 6 | Apr 30 |
| 28°F | May 26 | May 17 | May 10 | May 5 | May 2 | Apr 29 | Apr 24 | Apr 19 | Apr 13 |
| 24°F | May 5 | Apr 28 | Apr 22 | Apr 17 | Apr 12 | Apr 8 | Apr 3 | Mar 28 | Mar 15 |
| 20°F | Apr 17 | Apr 8 | Mar 31 | Mar 23 | Mar 15 | Mar 6 | Feb 28 | Feb 22 | Feb 11 |
| 16°F | Mar 20 | Mar 7 | Mar 1 | Feb 24 | Feb 18 | Feb 12 | Feb 6 | Feb 1 | Jan 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 | Aug 28 | Sep 2 | Sep 6 | Sep 9 | Sep 12 | Sep 16 | Sep 19 | Sep 24 | Sep 30 |
| 32°F | Sep 9 | Sep 18 | Sep 24 | Sep 28 | Oct 1 | Oct 4 | Oct 8 | Oct 13 | Oct 19 |
| 28°F | Sep 29 | Oct 4 | Oct 8 | Oct 13 | Oct 17 | Oct 21 | Oct 25 | Oct 30 | Nov 4 |
| 24°F | Oct 13 | Oct 19 | Oct 24 | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 15 |
| 20°F | Oct 27 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 24 | Dec 1 |
| 16°F | Nov 3 | Nov 9 | Nov 13 | Nov 18 | Nov 23 | Nov 27 | Dec 2 | Dec 7 | Dec 18 |
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 | 118 | 110 | 104 | 98 | 92 | 87 | 81 | 73 | 64 |
| 32°F | 159 | 150 | 143 | 137 | 130 | 125 | 119 | 112 | 104 |
| 28°F | 192 | 183 | 177 | 172 | 166 | 161 | 154 | 146 | 135 |
| 24°F | 228 | 218 | 211 | 205 | 200 | 194 | 187 | 181 | 171 |
| 20°F | 275 | 263 | 254 | 246 | 239 | 231 | 222 | 213 | 200 |
| 16°F | 313 | 300 | 290 | 283 | 276 | 269 | 262 | 253 | 243 |
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
- 5,680
- Cooling degree days, base 65°F
- 352
- Growing degree days, base 40°F
- 4,541
- Growing degree days, base 45°F
- 3,303
- Growing degree days, base 50°F
- 2,283
- Growing degree days, base 55°F
- 1,466
- Growing degree days, base 60°F
- 822
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 981 | 0 | 1 |
| February | 759 | 0 | 1 |
| March | 667 | 0 | 16 |
| April | 522 | 0 | 50 |
| May | 313 | 7 | 192 |
| June | 118 | 40 | 375 |
| July | 18 | 158 | 604 |
| August | 26 | 119 | 558 |
| September | 127 | 26 | 354 |
| October | 414 | 1 | 120 |
| November | 746 | 0 | 10 |
| December | 990 | 0 | 2 |
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 6.5 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 USC00042506 (Doyle 4 Sse). Public domain.