Eagleville Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Christiana 5W. 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 14 and the first fall freeze around October 25, a growing season of about 192 days.
- Median at 36°F
- last April 26, first October 17
- Median at 32°F
- last April 14, first October 25
- Median at 28°F
- last April 2, 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 12 | May 6 | May 1 | Apr 30 | Apr 26 | Apr 24 | Apr 21 | Apr 17 | Apr 12 |
| 32°F | Apr 30 | Apr 25 | Apr 21 | Apr 17 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Mar 31 |
| 28°F | Apr 18 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 27 | Mar 21 | Mar 14 |
| 24°F | Apr 7 | Apr 1 | Mar 29 | Mar 25 | Mar 21 | Mar 17 | Mar 13 | Mar 7 | Feb 28 |
| 20°F | Mar 28 | Mar 21 | Mar 16 | Mar 12 | Mar 8 | Mar 2 | Feb 27 | Feb 22 | Feb 13 |
| 16°F | Mar 17 | Mar 9 | Mar 3 | Feb 28 | Feb 23 | Feb 17 | Feb 10 | Feb 3 | Jan 27 |
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 | Oct 3 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 19 | Oct 21 | Oct 24 | Oct 28 |
| 32°F | Oct 11 | Oct 17 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 30 | Nov 1 | Nov 5 |
| 28°F | Oct 21 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 6 | Nov 8 | Nov 12 | Nov 18 |
| 24°F | Nov 1 | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 17 | Nov 21 | Nov 26 | Dec 1 |
| 20°F | Nov 9 | Nov 15 | Nov 19 | Nov 23 | Nov 28 | Dec 1 | Dec 5 | Dec 11 | Dec 20 |
| 16°F | Nov 21 | Nov 29 | Dec 3 | Dec 6 | Dec 11 | Dec 18 | Dec 23 | Dec 29 | Jan 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 | 192 | 185 | 180 | 176 | 172 | 168 | 165 | 160 | 152 |
| 32°F | 213 | 206 | 201 | 195 | 192 | 188 | 184 | 178 | 172 |
| 28°F | 238 | 230 | 224 | 219 | 215 | 210 | 206 | 201 | 195 |
| 24°F | 264 | 256 | 249 | 244 | 239 | 235 | 229 | 223 | 216 |
| 20°F | 295 | 284 | 277 | 270 | 265 | 259 | 253 | 247 | 239 |
| 16°F | 327 | 316 | 307 | 301 | 295 | 288 | 281 | 274 | 262 |
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
- 4,064
- Cooling degree days, base 65°F
- 1,248
- Growing degree days, base 40°F
- 6,840
- Growing degree days, base 45°F
- 5,407
- Growing degree days, base 50°F
- 4,129
- Growing degree days, base 55°F
- 3,020
- Growing degree days, base 60°F
- 2,061
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 883 | 0 | 18 |
| February | 696 | 1 | 31 |
| March | 535 | 3 | 94 |
| April | 275 | 20 | 234 |
| May | 92 | 90 | 467 |
| June | 4 | 242 | 688 |
| July | 0 | 351 | 815 |
| August | 1 | 331 | 795 |
| September | 31 | 178 | 597 |
| October | 233 | 30 | 287 |
| November | 530 | 2 | 75 |
| December | 783 | 0 | 28 |
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 15.3 km from Eagleville. 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 USC00401720 (Christiana 5W). Public domain.