Mishawaka Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for S Bend. 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 23 and the first fall freeze around October 23, a growing season of about 181 days.
- Median at 36°F
- last May 3, first October 12
- Median at 32°F
- last April 23, first October 23
- Median at 28°F
- last April 12, first November 3
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 13 | May 9 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 20 |
| 32°F | May 9 | May 3 | Apr 30 | Apr 26 | Apr 23 | Apr 21 | Apr 18 | Apr 15 | Apr 11 |
| 28°F | Apr 28 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 9 | Apr 5 | Apr 3 | Mar 30 |
| 24°F | Apr 16 | Apr 11 | Apr 6 | Apr 3 | Apr 1 | Mar 30 | Mar 27 | Mar 23 | Mar 17 |
| 20°F | Apr 5 | Mar 31 | Mar 29 | Mar 26 | Mar 23 | Mar 19 | Mar 16 | Mar 11 | Mar 4 |
| 16°F | Mar 29 | Mar 24 | Mar 19 | Mar 16 | Mar 12 | Mar 9 | Mar 5 | 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 | Sep 28 | Oct 2 | Oct 6 | Oct 9 | Oct 12 | Oct 14 | Oct 17 | Oct 20 | Oct 24 |
| 32°F | Oct 9 | Oct 14 | Oct 18 | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 28°F | Oct 21 | Oct 25 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 21 |
| 24°F | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 16 | Nov 20 | Nov 23 | Nov 27 | Dec 2 |
| 20°F | Nov 9 | Nov 14 | Nov 19 | Nov 23 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 15 |
| 16°F | Nov 19 | Nov 26 | Nov 30 | Dec 3 | Dec 6 | Dec 10 | Dec 14 | Dec 20 | Dec 24 |
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 | 178 | 172 | 167 | 164 | 161 | 157 | 152 | 146 | 140 |
| 32°F | 201 | 195 | 190 | 185 | 181 | 177 | 173 | 168 | 162 |
| 28°F | 227 | 219 | 213 | 208 | 205 | 200 | 196 | 190 | 183 |
| 24°F | 251 | 243 | 238 | 234 | 228 | 224 | 219 | 213 | 206 |
| 20°F | 274 | 266 | 260 | 254 | 250 | 245 | 240 | 234 | 226 |
| 16°F | 294 | 285 | 279 | 273 | 269 | 264 | 258 | 252 | 244 |
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
- 6,235
- Cooling degree days, base 65°F
- 737
- Growing degree days, base 40°F
- 5,078
- Growing degree days, base 45°F
- 3,961
- Growing degree days, base 50°F
- 2,979
- Growing degree days, base 55°F
- 2,120
- Growing degree days, base 60°F
- 1,364
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,256 | 0 | 0 |
| February | 1,066 | 0 | 0 |
| March | 868 | 0 | 5 |
| April | 495 | 5 | 96 |
| May | 193 | 36 | 322 |
| June | 21 | 160 | 588 |
| July | 1 | 248 | 712 |
| August | 8 | 202 | 658 |
| September | 93 | 79 | 438 |
| October | 402 | 6 | 136 |
| November | 748 | 1 | 22 |
| December | 1,085 | 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 8.6 km from Mishawaka. 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 USC00128437 (S Bend). Public domain.