Dante Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Nora 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 April 14 and the first fall freeze around November 1, a growing season of about 200 days.
- Median at 36°F
- last April 27, first October 22
- Median at 32°F
- last April 14, first November 1
- Median at 28°F
- last March 31, first November 8
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 15 | May 9 | May 5 | May 1 | Apr 27 | Apr 23 | Apr 18 | Apr 14 | Apr 9 |
| 32°F | May 5 | Apr 29 | Apr 22 | Apr 17 | Apr 14 | Apr 10 | Apr 6 | Apr 2 | Mar 29 |
| 28°F | Apr 20 | Apr 12 | Apr 6 | Apr 3 | Mar 31 | Mar 29 | Mar 26 | Mar 22 | Mar 16 |
| 24°F | Apr 6 | Apr 1 | Mar 29 | Mar 26 | Mar 22 | Mar 18 | Mar 15 | Mar 10 | Mar 4 |
| 20°F | Mar 30 | Mar 24 | Mar 19 | Mar 15 | Mar 12 | Mar 7 | Mar 3 | Feb 28 | Feb 19 |
| 16°F | Mar 22 | Mar 14 | Mar 9 | Mar 5 | Mar 1 | Feb 26 | Feb 19 | Feb 11 | Feb 2 |
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 12 | Oct 16 | Oct 18 | Oct 20 | Oct 22 | Oct 24 | Oct 27 | Oct 30 | Nov 2 |
| 32°F | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 12 |
| 28°F | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 8 | Nov 11 | Nov 14 | Nov 19 | Nov 25 |
| 24°F | Nov 4 | Nov 8 | Nov 11 | Nov 15 | Nov 20 | Nov 24 | Nov 28 | Dec 2 | Dec 8 |
| 20°F | Nov 11 | Nov 17 | Nov 22 | Nov 27 | Dec 1 | Dec 5 | Dec 11 | Dec 16 | Dec 25 |
| 16°F | Nov 21 | Nov 30 | Dec 5 | Dec 10 | Dec 16 | Dec 22 | Dec 27 | Dec 31 | Jan 7 |
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 | 198 | 192 | 187 | 183 | 179 | 175 | 170 | 165 | 157 |
| 32°F | 221 | 214 | 208 | 204 | 200 | 196 | 190 | 185 | 177 |
| 28°F | 245 | 237 | 231 | 227 | 223 | 219 | 214 | 208 | 200 |
| 24°F | 269 | 261 | 254 | 248 | 242 | 237 | 231 | 226 | 219 |
| 20°F | 294 | 284 | 277 | 271 | 265 | 259 | 252 | 245 | 237 |
| 16°F | 321 | 308 | 301 | 295 | 289 | 283 | 277 | 270 | 258 |
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
- 4,943
- Cooling degree days, base 65°F
- 757
- Growing degree days, base 40°F
- 5,823
- Growing degree days, base 45°F
- 4,497
- Growing degree days, base 50°F
- 3,331
- Growing degree days, base 55°F
- 2,322
- Growing degree days, base 60°F
- 1,460
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,013 | 0 | 8 |
| February | 823 | 0 | 14 |
| March | 685 | 1 | 53 |
| April | 363 | 10 | 177 |
| May | 156 | 47 | 368 |
| June | 16 | 143 | 577 |
| July | 5 | 220 | 680 |
| August | 4 | 212 | 673 |
| September | 66 | 105 | 490 |
| October | 307 | 18 | 226 |
| November | 620 | 1 | 52 |
| December | 885 | 0 | 14 |
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 4.6 km from Dante. 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 USC00446125 (Nora 4 Sse). Public domain.