Christopher Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Du Quoin 4 Se. 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 6 and the first fall freeze around October 22, a growing season of about 199 days.
- Median at 36°F
- last April 19, first October 12
- Median at 32°F
- last April 6, first October 22
- Median at 28°F
- last March 27, first November 2
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 4 | Apr 29 | Apr 25 | Apr 21 | Apr 19 | Apr 15 | Apr 12 | Apr 9 | Apr 4 |
| 32°F | Apr 22 | Apr 17 | Apr 13 | Apr 10 | Apr 6 | Apr 4 | Apr 1 | Mar 29 | Mar 23 |
| 28°F | Apr 11 | Apr 6 | Apr 2 | Mar 30 | Mar 27 | Mar 24 | Mar 20 | Mar 16 | Mar 10 |
| 24°F | Mar 31 | Mar 26 | Mar 22 | Mar 18 | Mar 15 | Mar 12 | Mar 8 | Mar 4 | Feb 28 |
| 20°F | Mar 21 | Mar 15 | Mar 12 | Mar 8 | Mar 5 | Mar 2 | Feb 27 | Feb 22 | Feb 13 |
| 16°F | Mar 14 | Mar 7 | Mar 3 | Feb 28 | Feb 24 | Feb 19 | Feb 12 | Feb 7 | Jan 31 |
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 29 | Oct 4 | Oct 7 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 26 |
| 32°F | Oct 9 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 25 | Oct 28 | Nov 1 | Nov 5 |
| 28°F | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 18 |
| 24°F | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 19 | Nov 24 | Nov 28 | Dec 3 |
| 20°F | Nov 8 | Nov 13 | Nov 18 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 10 | Dec 17 |
| 16°F | Nov 18 | Nov 26 | Dec 1 | Dec 5 | Dec 9 | Dec 14 | Dec 19 | Dec 25 | Jan 1 |
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 | 195 | 189 | 184 | 180 | 176 | 172 | 167 | 162 | 155 |
| 32°F | 218 | 212 | 206 | 202 | 199 | 194 | 189 | 184 | 177 |
| 28°F | 244 | 236 | 229 | 224 | 220 | 216 | 212 | 206 | 199 |
| 24°F | 268 | 260 | 254 | 248 | 243 | 238 | 233 | 229 | 222 |
| 20°F | 293 | 283 | 276 | 270 | 267 | 262 | 257 | 250 | 242 |
| 16°F | 316 | 307 | 300 | 293 | 287 | 281 | 275 | 268 | 259 |
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
- 4,564
- Cooling degree days, base 65°F
- 1,329
- Growing degree days, base 40°F
- 6,664
- Growing degree days, base 45°F
- 5,318
- Growing degree days, base 50°F
- 4,113
- Growing degree days, base 55°F
- 3,046
- Growing degree days, base 60°F
- 2,116
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,018 | 0 | 8 |
| February | 792 | 0 | 15 |
| March | 593 | 4 | 80 |
| April | 272 | 26 | 245 |
| May | 83 | 117 | 500 |
| June | 6 | 286 | 730 |
| July | 0 | 384 | 849 |
| August | 2 | 332 | 795 |
| September | 49 | 148 | 550 |
| October | 263 | 31 | 263 |
| November | 594 | 2 | 65 |
| December | 893 | 0 | 14 |
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 12.4 km from Christopher. 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 USC00112483 (Du Quoin 4 Se). Public domain.