Ida County Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Battle Creek 3NE. 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 1 and the first fall freeze around October 1, a growing season of about 153 days.
- Median at 36°F
- last May 10, first September 23
- Median at 32°F
- last May 1, first October 1
- Median at 28°F
- last April 21, first October 11
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 23 | May 19 | May 15 | May 12 | May 10 | May 7 | May 5 | May 2 | Apr 28 |
| 32°F | May 15 | May 9 | May 5 | May 3 | May 1 | Apr 28 | Apr 26 | Apr 23 | Apr 18 |
| 28°F | May 5 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 7 |
| 24°F | Apr 25 | Apr 20 | Apr 16 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Mar 30 |
| 20°F | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 29 | Mar 23 | Mar 17 |
| 16°F | Apr 9 | Apr 4 | Mar 31 | Mar 28 | Mar 25 | Mar 21 | Mar 17 | Mar 12 | Mar 7 |
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 11 | Sep 15 | Sep 18 | Sep 20 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 6 |
| 32°F | Sep 18 | Sep 22 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 |
| 28°F | Sep 26 | Oct 1 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 25 |
| 24°F | Oct 5 | Oct 13 | Oct 17 | Oct 20 | Oct 22 | Oct 24 | Oct 26 | Oct 30 | Nov 3 |
| 20°F | Oct 18 | Oct 22 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 4 | Nov 8 | Nov 12 |
| 16°F | Oct 27 | Nov 1 | Nov 3 | Nov 5 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 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 | 154 | 147 | 143 | 139 | 136 | 133 | 129 | 125 | 118 |
| 32°F | 172 | 165 | 160 | 157 | 153 | 149 | 145 | 140 | 134 |
| 28°F | 190 | 183 | 179 | 176 | 171 | 167 | 164 | 159 | 152 |
| 24°F | 210 | 203 | 199 | 194 | 191 | 187 | 183 | 178 | 170 |
| 20°F | 230 | 224 | 218 | 214 | 210 | 206 | 202 | 197 | 191 |
| 16°F | 251 | 243 | 238 | 232 | 228 | 223 | 219 | 213 | 206 |
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
- 7,304
- Cooling degree days, base 65°F
- 755
- Growing degree days, base 40°F
- 4,885
- Growing degree days, base 45°F
- 3,827
- Growing degree days, base 50°F
- 2,885
- Growing degree days, base 55°F
- 2,055
- Growing degree days, base 60°F
- 1,339
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,469 | 0 | 0 |
| February | 1,208 | 0 | 1 |
| March | 952 | 1 | 19 |
| April | 541 | 5 | 91 |
| May | 222 | 51 | 321 |
| June | 31 | 171 | 591 |
| July | 7 | 258 | 716 |
| August | 20 | 189 | 634 |
| September | 144 | 75 | 391 |
| October | 496 | 6 | 113 |
| November | 908 | 0 | 9 |
| December | 1,306 | 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 5.4 km from Ida County. 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 USC00130512 (Battle Creek 3NE). Public domain.