Wagner Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Wagner. 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 29 and the first fall freeze around October 9, a growing season of about 164 days.
- Median at 36°F
- last May 7, first October 1
- Median at 32°F
- last April 29, first October 9
- Median at 28°F
- last April 18, first October 19
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 21 | May 15 | May 13 | May 10 | May 7 | May 5 | May 2 | Apr 30 | Apr 25 |
| 32°F | May 12 | May 6 | May 3 | May 1 | Apr 29 | Apr 26 | Apr 22 | Apr 18 | Apr 12 |
| 28°F | May 2 | Apr 28 | Apr 25 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 8 | Apr 4 |
| 24°F | Apr 24 | Apr 19 | Apr 15 | Apr 12 | Apr 8 | Apr 6 | Apr 3 | Mar 31 | Mar 24 |
| 20°F | Apr 16 | Apr 10 | Apr 6 | Apr 3 | Apr 1 | Mar 29 | Mar 24 | Mar 19 | Mar 12 |
| 16°F | Apr 8 | Apr 3 | Mar 31 | Mar 27 | Mar 22 | Mar 18 | Mar 14 | Mar 10 | Mar 4 |
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 19 | Sep 23 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 14 |
| 32°F | Sep 25 | Sep 29 | Oct 3 | Oct 6 | Oct 9 | Oct 13 | Oct 16 | Oct 19 | Oct 23 |
| 28°F | Oct 3 | Oct 9 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Nov 2 |
| 24°F | Oct 14 | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 13 |
| 20°F | Oct 22 | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 21 |
| 16°F | Oct 30 | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 30 |
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 | 165 | 159 | 154 | 151 | 146 | 142 | 138 | 134 | 128 |
| 32°F | 183 | 177 | 172 | 168 | 164 | 160 | 156 | 151 | 144 |
| 28°F | 203 | 196 | 191 | 186 | 182 | 178 | 174 | 167 | 160 |
| 24°F | 224 | 214 | 209 | 205 | 202 | 198 | 193 | 188 | 181 |
| 20°F | 242 | 234 | 228 | 224 | 218 | 214 | 209 | 204 | 197 |
| 16°F | 259 | 253 | 247 | 242 | 237 | 233 | 228 | 222 | 214 |
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
- 6,543
- Cooling degree days, base 65°F
- 1,025
- Growing degree days, base 40°F
- 5,436
- Growing degree days, base 45°F
- 4,308
- Growing degree days, base 50°F
- 3,301
- Growing degree days, base 55°F
- 2,415
- Growing degree days, base 60°F
- 1,653
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,319 | 0 | 0 |
| February | 1,078 | 0 | 2 |
| March | 851 | 0 | 23 |
| April | 488 | 6 | 107 |
| May | 187 | 56 | 347 |
| June | 24 | 204 | 630 |
| July | 2 | 352 | 815 |
| August | 8 | 283 | 739 |
| September | 96 | 112 | 471 |
| October | 435 | 11 | 147 |
| November | 836 | 0 | 20 |
| December | 1,220 | 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 0.5 km from Wagner. 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 USC00398767 (Wagner). Public domain.