Vici Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Mutual. 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 19 and the first fall freeze around October 26, a growing season of about 188 days.
- Median at 36°F
- last April 28, first October 16
- Median at 32°F
- last April 19, first October 26
- Median at 28°F
- last April 7, first November 2
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 10 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 25 | Apr 21 | Apr 18 | Apr 13 |
| 32°F | May 3 | Apr 29 | Apr 25 | Apr 22 | Apr 19 | Apr 16 | Apr 13 | Apr 9 | Apr 1 |
| 28°F | Apr 23 | Apr 19 | Apr 15 | Apr 10 | Apr 7 | Apr 4 | Mar 31 | Mar 27 | Mar 19 |
| 24°F | Apr 12 | Apr 6 | Apr 2 | Mar 30 | Mar 26 | Mar 20 | Mar 16 | Mar 11 | Mar 4 |
| 20°F | Apr 1 | Mar 25 | Mar 18 | Mar 13 | Mar 10 | Mar 6 | Mar 3 | Feb 28 | Feb 22 |
| 16°F | Mar 17 | Mar 11 | Mar 6 | Mar 3 | Feb 28 | Feb 25 | Feb 20 | Feb 15 | Feb 5 |
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 2 | Oct 7 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Oct 30 |
| 32°F | Oct 11 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 28 | Nov 1 | Nov 4 | Nov 8 |
| 28°F | Oct 19 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 16 |
| 24°F | Oct 25 | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 13 | Nov 17 | Nov 22 | Nov 27 |
| 20°F | Nov 3 | Nov 9 | Nov 13 | Nov 18 | Nov 21 | Nov 24 | Nov 28 | Dec 2 | Dec 9 |
| 16°F | Nov 12 | Nov 19 | Nov 24 | Nov 27 | Dec 1 | Dec 5 | Dec 10 | Dec 16 | Dec 23 |
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 | 190 | 182 | 178 | 174 | 171 | 167 | 163 | 158 | 152 |
| 32°F | 210 | 203 | 197 | 192 | 188 | 184 | 181 | 176 | 168 |
| 28°F | 232 | 225 | 219 | 214 | 209 | 205 | 201 | 195 | 189 |
| 24°F | 255 | 247 | 241 | 235 | 230 | 225 | 220 | 214 | 206 |
| 20°F | 279 | 270 | 264 | 259 | 254 | 249 | 243 | 236 | 226 |
| 16°F | 306 | 296 | 289 | 283 | 277 | 271 | 266 | 260 | 252 |
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
- 4,375
- Cooling degree days, base 65°F
- 1,698
- Growing degree days, base 40°F
- 7,110
- Growing degree days, base 45°F
- 5,732
- Growing degree days, base 50°F
- 4,505
- Growing degree days, base 55°F
- 3,429
- Growing degree days, base 60°F
- 2,497
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 932 | 0 | 6 |
| February | 752 | 0 | 18 |
| March | 559 | 4 | 90 |
| April | 299 | 23 | 222 |
| May | 94 | 124 | 498 |
| June | 5 | 338 | 783 |
| July | 1 | 494 | 958 |
| August | 1 | 450 | 914 |
| September | 36 | 222 | 637 |
| October | 238 | 42 | 301 |
| November | 575 | 2 | 70 |
| December | 885 | 0 | 7 |
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 14.4 km from Vici. 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 USC00346139 (Mutual). Public domain.