Woods Cross Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Bountiful-Val Verda. 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 24 and the first fall freeze around October 19, a growing season of about 178 days.
- Median at 36°F
- last May 9, first October 9
- Median at 32°F
- last April 24, first October 19
- Median at 28°F
- last April 7, 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 | Jun 1 | May 23 | May 17 | May 12 | May 9 | May 5 | May 2 | Apr 29 | Apr 23 |
| 32°F | May 14 | May 6 | Apr 30 | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 12 | Apr 5 |
| 28°F | Apr 28 | Apr 22 | Apr 16 | Apr 11 | Apr 7 | Apr 3 | Mar 31 | Mar 24 | Mar 15 |
| 24°F | Apr 11 | Apr 4 | Mar 31 | Mar 26 | Mar 19 | Mar 13 | Mar 9 | Mar 5 | Feb 26 |
| 20°F | Mar 24 | Mar 13 | Mar 8 | Mar 4 | Mar 1 | Feb 25 | Feb 20 | Feb 15 | Feb 8 |
| 16°F | Mar 4 | Feb 27 | Feb 21 | Feb 16 | Feb 12 | Feb 8 | Feb 4 | Jan 31 | 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 | Sep 28 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 22 |
| 32°F | Oct 5 | Oct 9 | Oct 13 | Oct 17 | Oct 19 | Oct 23 | Oct 26 | Oct 31 | Nov 4 |
| 28°F | Oct 16 | Oct 22 | Oct 26 | Oct 30 | Nov 1 | Nov 4 | Nov 8 | Nov 12 | Nov 17 |
| 24°F | Oct 27 | Nov 1 | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 19 | Nov 23 | Nov 27 |
| 20°F | Nov 5 | Nov 11 | Nov 15 | Nov 19 | Nov 22 | Nov 25 | Nov 29 | Dec 3 | Dec 10 |
| 16°F | Nov 14 | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 7 | Dec 12 | Dec 18 | Dec 27 |
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 | 173 | 166 | 161 | 156 | 152 | 147 | 143 | 136 | 127 |
| 32°F | 201 | 194 | 188 | 183 | 178 | 173 | 169 | 163 | 155 |
| 28°F | 233 | 225 | 218 | 213 | 208 | 202 | 197 | 190 | 181 |
| 24°F | 267 | 257 | 250 | 244 | 238 | 232 | 227 | 220 | 211 |
| 20°F | 296 | 287 | 279 | 273 | 267 | 262 | 256 | 249 | 238 |
| 16°F | 325 | 315 | 307 | 301 | 294 | 288 | 282 | 275 | 266 |
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
- 5,725
- Cooling degree days, base 65°F
- 989
- Growing degree days, base 40°F
- 5,388
- Growing degree days, base 45°F
- 4,194
- Growing degree days, base 50°F
- 3,174
- Growing degree days, base 55°F
- 2,309
- Growing degree days, base 60°F
- 1,587
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,086 | 0 | 0 |
| February | 858 | 0 | 2 |
| March | 682 | 0 | 25 |
| April | 489 | 3 | 87 |
| May | 236 | 36 | 288 |
| June | 63 | 159 | 547 |
| July | 4 | 375 | 837 |
| August | 6 | 317 | 776 |
| September | 92 | 93 | 457 |
| October | 407 | 5 | 140 |
| November | 749 | 0 | 15 |
| December | 1,054 | 0 | 1 |
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 1.9 km from Woods Cross. 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 USC00420820 (Bountiful-Val Verda). Public domain.