Taylor Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Detroit Metro AP. 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 20 and the first fall freeze around October 27, a growing season of about 188 days.
- Median at 36°F
- last May 2, first October 15
- Median at 32°F
- last April 20, first October 27
- Median at 28°F
- last April 8, first November 7
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 18 | May 12 | May 9 | May 5 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 18 |
| 32°F | May 8 | May 2 | Apr 28 | Apr 23 | Apr 20 | Apr 17 | Apr 15 | Apr 12 | Apr 6 |
| 28°F | Apr 24 | Apr 18 | Apr 15 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 27 |
| 24°F | Apr 10 | Apr 5 | Apr 3 | Mar 31 | Mar 29 | Mar 26 | Mar 22 | Mar 19 | Mar 14 |
| 20°F | Apr 1 | Mar 29 | Mar 25 | Mar 22 | Mar 19 | Mar 16 | Mar 13 | Mar 10 | Mar 4 |
| 16°F | Mar 25 | Mar 20 | Mar 17 | Mar 14 | Mar 11 | Mar 7 | Mar 4 | Feb 28 | Feb 22 |
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 6 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 29 |
| 32°F | Oct 14 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 9 |
| 28°F | Oct 27 | Nov 1 | Nov 3 | Nov 5 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 22 |
| 24°F | Nov 5 | Nov 9 | Nov 13 | Nov 16 | Nov 19 | Nov 22 | Nov 26 | Nov 29 | Dec 5 |
| 20°F | Nov 13 | Nov 18 | Nov 23 | Nov 26 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 19 |
| 16°F | Nov 22 | Nov 30 | Dec 2 | Dec 6 | Dec 10 | Dec 14 | Dec 18 | Dec 22 | Dec 26 |
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 | 186 | 178 | 174 | 169 | 165 | 161 | 156 | 151 | 146 |
| 32°F | 207 | 201 | 196 | 192 | 188 | 184 | 180 | 174 | 167 |
| 28°F | 232 | 225 | 221 | 216 | 212 | 208 | 204 | 199 | 193 |
| 24°F | 257 | 249 | 244 | 239 | 235 | 231 | 226 | 222 | 216 |
| 20°F | 277 | 271 | 265 | 260 | 256 | 251 | 246 | 241 | 234 |
| 16°F | 300 | 290 | 284 | 279 | 275 | 271 | 265 | 259 | 250 |
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
- 6,067
- Cooling degree days, base 65°F
- 847
- Growing degree days, base 40°F
- 5,293
- Growing degree days, base 45°F
- 4,134
- Growing degree days, base 50°F
- 3,114
- Growing degree days, base 55°F
- 2,227
- Growing degree days, base 60°F
- 1,469
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,217 | 0 | 1 |
| February | 1,036 | 0 | 1 |
| March | 861 | 1 | 20 |
| April | 488 | 5 | 93 |
| May | 198 | 50 | 329 |
| June | 28 | 177 | 599 |
| July | 2 | 283 | 746 |
| August | 7 | 233 | 691 |
| September | 91 | 90 | 450 |
| October | 382 | 10 | 157 |
| November | 713 | 0 | 26 |
| December | 1,046 | 0 | 3 |
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 5.1 km from Taylor. 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 USW00094847 (Detroit Metro AP). Public domain.