Fox Point Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Mt Mary College. 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 26 and the first fall freeze around October 18, a growing season of about 173 days.
- Median at 36°F
- last May 8, first October 6
- Median at 32°F
- last April 26, first October 18
- Median at 28°F
- last April 14, first October 30
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 24 | May 19 | May 15 | May 11 | May 8 | May 5 | May 2 | Apr 30 | Apr 24 |
| 32°F | May 12 | May 6 | May 2 | Apr 29 | Apr 26 | Apr 23 | Apr 20 | Apr 16 | Apr 12 |
| 28°F | Apr 30 | Apr 24 | Apr 20 | Apr 16 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 1 |
| 24°F | Apr 17 | Apr 12 | Apr 9 | Apr 6 | Apr 4 | Apr 2 | Mar 31 | Mar 27 | Mar 20 |
| 20°F | Apr 7 | Apr 3 | Mar 31 | Mar 28 | Mar 25 | Mar 22 | Mar 18 | Mar 15 | Mar 10 |
| 16°F | Mar 31 | Mar 25 | Mar 22 | Mar 18 | Mar 15 | Mar 12 | Mar 9 | Mar 6 | Mar 1 |
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 25 | Sep 29 | Oct 2 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 16 | Oct 22 |
| 32°F | Oct 2 | Oct 7 | Oct 12 | Oct 15 | Oct 18 | Oct 22 | Oct 24 | Oct 27 | Nov 1 |
| 28°F | Oct 13 | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 11 |
| 24°F | Oct 27 | Nov 1 | Nov 3 | Nov 5 | Nov 9 | Nov 11 | Nov 14 | Nov 18 | Nov 23 |
| 20°F | Nov 4 | Nov 10 | Nov 12 | Nov 16 | Nov 19 | Nov 22 | Nov 25 | Nov 29 | Dec 4 |
| 16°F | Nov 12 | Nov 18 | Nov 21 | Nov 25 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 16 |
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 | 168 | 163 | 158 | 154 | 150 | 146 | 142 | 137 | 130 |
| 32°F | 192 | 186 | 181 | 177 | 173 | 169 | 165 | 161 | 153 |
| 28°F | 217 | 210 | 205 | 200 | 196 | 192 | 188 | 184 | 178 |
| 24°F | 237 | 231 | 227 | 223 | 220 | 216 | 212 | 208 | 202 |
| 20°F | 260 | 253 | 249 | 244 | 239 | 236 | 231 | 226 | 219 |
| 16°F | 278 | 271 | 265 | 261 | 257 | 252 | 248 | 243 | 236 |
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
- 6,792
- Cooling degree days, base 65°F
- 728
- Growing degree days, base 40°F
- 4,841
- Growing degree days, base 45°F
- 3,753
- Growing degree days, base 50°F
- 2,804
- Growing degree days, base 55°F
- 1,982
- Growing degree days, base 60°F
- 1,287
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,336 | 0 | 0 |
| February | 1,116 | 0 | 1 |
| March | 928 | 1 | 16 |
| April | 568 | 3 | 64 |
| May | 269 | 36 | 260 |
| June | 57 | 144 | 537 |
| July | 7 | 256 | 715 |
| August | 12 | 204 | 657 |
| September | 120 | 76 | 410 |
| October | 434 | 8 | 129 |
| November | 796 | 0 | 14 |
| December | 1,150 | 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 14.1 km from Fox Point. 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 USC00475474 (Mt Mary College). Public domain.