Onaway Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Onaway 4N. 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 May 22 and the first fall freeze around October 2, a growing season of about 135 days.
- Median at 36°F
- last June 2, first September 19
- Median at 32°F
- last May 22, first October 2
- Median at 28°F
- last May 7, first October 16
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 | Jun 16 | Jun 10 | Jun 7 | Jun 4 | Jun 2 | May 31 | May 28 | May 25 | May 21 |
| 32°F | Jun 2 | May 30 | May 27 | May 24 | May 22 | May 19 | May 15 | May 11 | May 3 |
| 28°F | May 24 | May 19 | May 15 | May 11 | May 7 | May 4 | Apr 30 | Apr 28 | Apr 25 |
| 24°F | May 12 | May 4 | Apr 30 | Apr 28 | Apr 25 | Apr 23 | Apr 19 | Apr 16 | Apr 11 |
| 20°F | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 | Apr 4 | Mar 31 |
| 16°F | Apr 18 | Apr 13 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 30 | Mar 27 | Mar 21 |
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 2 | Sep 7 | Sep 12 | Sep 16 | Sep 19 | Sep 22 | Sep 25 | Sep 29 | Oct 3 |
| 32°F | Sep 16 | Sep 21 | Sep 25 | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 16 |
| 28°F | Sep 26 | Oct 3 | Oct 7 | Oct 12 | Oct 16 | Oct 19 | Oct 23 | Oct 27 | Nov 1 |
| 24°F | Oct 15 | Oct 21 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 16 |
| 20°F | Oct 31 | Nov 3 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Dec 1 |
| 16°F | Nov 8 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 4 | Dec 11 |
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 | 128 | 121 | 117 | 112 | 108 | 103 | 99 | 93 | 83 |
| 32°F | 156 | 148 | 143 | 139 | 135 | 131 | 125 | 119 | 112 |
| 28°F | 182 | 174 | 169 | 165 | 160 | 156 | 151 | 146 | 137 |
| 24°F | 211 | 204 | 198 | 194 | 190 | 185 | 180 | 175 | 166 |
| 20°F | 236 | 228 | 223 | 219 | 214 | 210 | 206 | 200 | 192 |
| 16°F | 257 | 249 | 243 | 239 | 234 | 230 | 226 | 221 | 212 |
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
- 7,815
- Cooling degree days, base 65°F
- 359
- Growing degree days, base 40°F
- 3,935
- Growing degree days, base 45°F
- 2,955
- Growing degree days, base 50°F
- 2,106
- Growing degree days, base 55°F
- 1,377
- Growing degree days, base 60°F
- 783
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,415 | 0 | 0 |
| February | 1,245 | 0 | 0 |
| March | 1,096 | 0 | 7 |
| April | 707 | 2 | 33 |
| May | 353 | 18 | 185 |
| June | 110 | 67 | 408 |
| July | 33 | 128 | 559 |
| August | 47 | 103 | 521 |
| September | 198 | 39 | 304 |
| October | 537 | 4 | 81 |
| November | 861 | 0 | 9 |
| December | 1,214 | 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 5.9 km from Onaway. 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 USC00206184 (Onaway 4N). Public domain.