Culp Creek Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Dorena. 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 16 and the first fall freeze around October 28, a growing season of about 194 days.
- Median at 36°F
- last May 9, first October 5
- Median at 32°F
- last April 16, first October 28
- Median at 28°F
- last March 12, first November 21
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 2 | May 25 | May 18 | May 14 | May 9 | May 5 | May 1 | Apr 27 | Apr 20 |
| 32°F | May 11 | May 2 | Apr 27 | Apr 22 | Apr 16 | Apr 10 | Apr 4 | Mar 31 | Mar 24 |
| 28°F | Apr 13 | Apr 2 | Mar 26 | Mar 19 | Mar 12 | Mar 6 | Mar 1 | Feb 23 | Feb 12 |
| 24°F | Mar 8 | Feb 28 | Feb 24 | Feb 18 | Feb 14 | Feb 7 | Jan 28 | Jan 11 | Dec 23 |
| 20°F | Feb 21 | Feb 15 | Feb 8 | Jan 31 | Jan 17 | Jan 4 | Dec 29 | Dec 20 | Dec 10 |
| 16°F | Feb 8 | Jan 24 | Jan 9 | Dec 31 | Dec 28 | Dec 23 | Dec 17 | Dec 12 | Dec 8 |
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 | Sep 14 | Sep 23 | Sep 28 | Oct 1 | Oct 5 | Oct 9 | Oct 14 | Oct 20 | Oct 29 |
| 32°F | Oct 4 | Oct 13 | Oct 19 | Oct 23 | Oct 28 | Nov 1 | Nov 5 | Nov 12 | Nov 23 |
| 28°F | Oct 24 | Nov 1 | Nov 7 | Nov 14 | Nov 21 | Nov 28 | Dec 3 | Dec 12 | Dec 23 |
| 24°F | Nov 6 | Nov 22 | Dec 1 | Dec 8 | Dec 17 | Dec 24 | Dec 31 | Jan 16 | Feb 9 |
| 20°F | Nov 29 | Dec 8 | Dec 16 | Dec 21 | Dec 27 | Jan 1 | Jan 17 | Feb 1 | Feb 13 |
| 16°F | Dec 6 | Dec 9 | Dec 14 | Dec 20 | Dec 23 | Dec 28 | Dec 31 | Jan 11 | Feb 4 |
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 | 179 | 170 | 161 | 155 | 149 | 143 | 136 | 128 | 117 |
| 32°F | 228 | 218 | 208 | 201 | 194 | 187 | 180 | 170 | 157 |
| 28°F | 296 | 281 | 270 | 261 | 252 | 242 | 233 | 223 | 209 |
| 24°F | 360 | 342 | 331 | 319 | 310 | 301 | 292 | 279 | 263 |
| 20°F | 365 | 365 | 365 | 365 | 358 | 349 | 339 | 328 | 313 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 360 | 345 |
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
- 91% of years
- 20°F or colder
- 53% of years
- 16°F or colder
- 20% 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
- 4,933
- Cooling degree days, base 65°F
- 200
- Growing degree days, base 40°F
- 4,595
- Growing degree days, base 45°F
- 3,160
- Growing degree days, base 50°F
- 2,028
- Growing degree days, base 55°F
- 1,178
- Growing degree days, base 60°F
- 567
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 749 | 0 | 4 |
| February | 630 | 0 | 6 |
| March | 601 | 0 | 21 |
| April | 471 | 0 | 58 |
| May | 308 | 5 | 180 |
| June | 177 | 18 | 292 |
| July | 46 | 79 | 498 |
| August | 46 | 74 | 493 |
| September | 141 | 22 | 333 |
| October | 385 | 1 | 119 |
| November | 600 | 0 | 21 |
| December | 778 | 0 | 4 |
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 12.7 km from Culp Creek. 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 USC00352374 (Dorena). Public domain.