Milo Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Indianola 2W. 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 24 and the first fall freeze around October 12, a growing season of about 168 days.
- Median at 36°F
- last May 4, first October 2
- Median at 32°F
- last April 24, first October 12
- Median at 28°F
- last April 14, first October 21
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 19 | May 13 | May 9 | May 6 | May 4 | May 2 | Apr 30 | Apr 25 | Apr 20 |
| 32°F | May 8 | May 4 | May 1 | Apr 28 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 11 |
| 28°F | Apr 29 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 12 | Apr 8 | Apr 5 | Apr 1 |
| 24°F | Apr 20 | Apr 14 | Apr 10 | Apr 7 | Apr 4 | Apr 1 | Mar 30 | Mar 25 | Mar 19 |
| 20°F | Apr 11 | Apr 5 | Apr 1 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 13 | Mar 9 |
| 16°F | Apr 1 | Mar 28 | Mar 23 | Mar 19 | Mar 15 | Mar 13 | Mar 9 | Mar 5 | Feb 28 |
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 19 | Sep 23 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 7 | Oct 11 | Oct 15 |
| 32°F | Sep 27 | Oct 1 | Oct 6 | Oct 9 | Oct 12 | Oct 14 | Oct 18 | Oct 21 | Oct 26 |
| 28°F | Oct 6 | Oct 12 | Oct 16 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 4 |
| 24°F | Oct 18 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 9 | Nov 14 |
| 20°F | Oct 28 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 16 | Nov 20 | Nov 27 |
| 16°F | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 4 |
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 | 161 | 156 | 153 | 149 | 144 | 141 | 135 | 128 |
| 32°F | 188 | 181 | 176 | 171 | 168 | 164 | 159 | 155 | 147 |
| 28°F | 209 | 201 | 196 | 192 | 188 | 184 | 180 | 175 | 169 |
| 24°F | 230 | 222 | 217 | 213 | 208 | 204 | 199 | 195 | 188 |
| 20°F | 252 | 244 | 239 | 234 | 230 | 225 | 220 | 214 | 207 |
| 16°F | 271 | 264 | 257 | 252 | 248 | 244 | 240 | 234 | 226 |
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
- 6,417
- Cooling degree days, base 65°F
- 934
- Growing degree days, base 40°F
- 5,421
- Growing degree days, base 45°F
- 4,274
- Growing degree days, base 50°F
- 3,252
- Growing degree days, base 55°F
- 2,352
- Growing degree days, base 60°F
- 1,578
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,344 | 0 | 0 |
| February | 1,099 | 0 | 2 |
| March | 830 | 2 | 34 |
| April | 458 | 8 | 121 |
| May | 183 | 56 | 350 |
| June | 24 | 194 | 621 |
| July | 3 | 305 | 767 |
| August | 7 | 249 | 707 |
| September | 106 | 105 | 454 |
| October | 404 | 15 | 168 |
| November | 788 | 0 | 27 |
| December | 1,173 | 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 19.1 km from Milo. 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 USC00134063 (Indianola 2W). Public domain.