Suttons Bay Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Nw Michigan Rsch Farm. 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 30 and the first fall freeze around November 1, a growing season of about 182 days.
- Median at 36°F
- last May 13, first October 16
- Median at 32°F
- last April 30, first November 1
- Median at 28°F
- last April 18, first November 12
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 27 | May 23 | May 19 | May 16 | May 13 | May 9 | May 6 | May 2 | Apr 28 |
| 32°F | May 15 | May 10 | May 5 | May 3 | Apr 30 | Apr 28 | Apr 25 | Apr 21 | Apr 16 |
| 28°F | May 4 | Apr 29 | Apr 25 | Apr 21 | Apr 18 | Apr 15 | Apr 13 | Apr 9 | Apr 4 |
| 24°F | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 4 | Apr 1 | Mar 29 | Mar 22 |
| 20°F | Apr 11 | Apr 6 | Apr 3 | Apr 1 | Mar 30 | Mar 27 | Mar 23 | Mar 18 | Mar 13 |
| 16°F | Apr 3 | Mar 30 | Mar 26 | Mar 23 | Mar 19 | Mar 15 | Mar 12 | Mar 9 | 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 | Oct 1 | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 23 | Oct 27 | Nov 1 |
| 32°F | Oct 16 | Oct 22 | Oct 26 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 14 |
| 28°F | Nov 1 | Nov 3 | Nov 7 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 22 | Nov 27 |
| 24°F | Nov 8 | Nov 13 | Nov 16 | Nov 20 | Nov 23 | Nov 27 | Nov 30 | Dec 4 | Dec 9 |
| 20°F | Nov 17 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 7 | Dec 11 | Dec 16 | Dec 22 |
| 16°F | Nov 27 | Dec 2 | Dec 7 | Dec 12 | Dec 16 | Dec 20 | Dec 24 | Dec 30 | Jan 5 |
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 | 177 | 170 | 165 | 160 | 156 | 152 | 148 | 143 | 135 |
| 32°F | 202 | 195 | 190 | 186 | 182 | 179 | 174 | 169 | 161 |
| 28°F | 228 | 221 | 216 | 212 | 208 | 204 | 200 | 195 | 187 |
| 24°F | 252 | 244 | 240 | 236 | 231 | 227 | 223 | 218 | 211 |
| 20°F | 273 | 265 | 259 | 254 | 250 | 246 | 241 | 235 | 228 |
| 16°F | 294 | 286 | 281 | 277 | 272 | 267 | 261 | 255 | 247 |
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
- 7,165
- Cooling degree days, base 65°F
- 486
- Growing degree days, base 40°F
- 4,306
- Growing degree days, base 45°F
- 3,280
- Growing degree days, base 50°F
- 2,387
- Growing degree days, base 55°F
- 1,620
- Growing degree days, base 60°F
- 978
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,303 | 0 | 0 |
| February | 1,154 | 0 | 0 |
| March | 1,041 | 1 | 10 |
| April | 670 | 1 | 40 |
| May | 332 | 21 | 205 |
| June | 87 | 90 | 455 |
| July | 22 | 172 | 615 |
| August | 23 | 142 | 584 |
| September | 147 | 54 | 363 |
| October | 475 | 6 | 102 |
| November | 794 | 0 | 12 |
| December | 1,118 | 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 10.6 km from Suttons Bay. 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 USC00206012 (Nw Michigan Rsch Farm). Public domain.