Verdi Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Verdi 2W. 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 9 and the first fall freeze around October 17, a growing season of about 156 days.
- Median at 36°F
- last May 31, first October 5
- Median at 32°F
- last May 9, first October 17
- Median at 28°F
- last April 24, first October 31
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 16 | Jun 10 | Jun 5 | Jun 2 | May 31 | May 27 | May 23 | May 17 | May 11 |
| 32°F | Jun 2 | May 26 | May 19 | May 14 | May 9 | May 5 | May 2 | Apr 29 | Apr 23 |
| 28°F | May 16 | May 7 | May 1 | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 12 | Apr 7 |
| 24°F | Apr 25 | Apr 18 | Apr 14 | Apr 10 | Apr 6 | Apr 2 | Mar 29 | Mar 20 | Mar 10 |
| 20°F | Apr 9 | Apr 2 | Mar 27 | Mar 20 | Mar 14 | Mar 8 | Mar 2 | Feb 25 | Feb 16 |
| 16°F | Mar 20 | Mar 10 | Mar 4 | Feb 28 | Feb 22 | Feb 17 | Feb 11 | Feb 2 | Jan 17 |
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 16 | Sep 25 | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 19 |
| 32°F | Oct 1 | Oct 5 | Oct 9 | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 29 | Nov 3 |
| 28°F | Oct 13 | Oct 19 | Oct 23 | Oct 27 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 16 |
| 24°F | Oct 26 | Nov 1 | Nov 5 | Nov 9 | Nov 11 | Nov 16 | Nov 19 | Nov 23 | Nov 29 |
| 20°F | Nov 5 | Nov 12 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 9 |
| 16°F | Nov 13 | Nov 21 | Nov 28 | Dec 2 | Dec 6 | Dec 10 | Dec 14 | Dec 19 | Jan 1 |
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 | 151 | 142 | 135 | 130 | 125 | 120 | 116 | 109 | 99 |
| 32°F | 181 | 172 | 166 | 161 | 156 | 150 | 144 | 136 | 125 |
| 28°F | 212 | 204 | 197 | 192 | 188 | 183 | 177 | 170 | 161 |
| 24°F | 248 | 237 | 229 | 224 | 219 | 213 | 207 | 200 | 191 |
| 20°F | 285 | 273 | 266 | 259 | 252 | 246 | 239 | 231 | 217 |
| 16°F | 324 | 311 | 301 | 294 | 286 | 278 | 271 | 262 | 251 |
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
- 99% 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
- 6,084
- Cooling degree days, base 65°F
- 342
- Growing degree days, base 40°F
- 4,276
- Growing degree days, base 45°F
- 3,115
- Growing degree days, base 50°F
- 2,167
- Growing degree days, base 55°F
- 1,400
- Growing degree days, base 60°F
- 801
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 986 | 0 | 0 |
| February | 834 | 0 | 2 |
| March | 766 | 0 | 9 |
| April | 612 | 0 | 26 |
| May | 387 | 4 | 136 |
| June | 158 | 43 | 344 |
| July | 21 | 141 | 586 |
| August | 19 | 109 | 555 |
| September | 131 | 42 | 373 |
| October | 433 | 4 | 119 |
| November | 729 | 0 | 18 |
| December | 1,008 | 0 | 0 |
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 3.3 km from Verdi. 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 USC00049298 (Verdi 2W). Public domain.