Gresham Park Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Atlanta Hartsfield Intl AP. 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 March 15 and the first fall freeze around November 20, a growing season of about 252 days.
- Median at 36°F
- last March 29, first November 7
- Median at 32°F
- last March 15, first November 20
- Median at 28°F
- last February 28, first December 5
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 | Apr 16 | Apr 10 | Apr 5 | Apr 2 | Mar 29 | Mar 25 | Mar 20 | Mar 16 | Mar 10 |
| 32°F | Apr 4 | Mar 28 | Mar 23 | Mar 18 | Mar 15 | Mar 12 | Mar 7 | Mar 1 | Feb 23 |
| 28°F | Mar 20 | Mar 15 | Mar 10 | Mar 4 | Feb 28 | Feb 25 | Feb 19 | Feb 11 | Feb 1 |
| 24°F | Mar 12 | Mar 3 | Feb 26 | Feb 18 | Feb 11 | Feb 3 | Jan 30 | Jan 22 | Jan 12 |
| 20°F | Feb 28 | Feb 17 | Feb 6 | Feb 1 | Jan 28 | Jan 22 | Jan 16 | Jan 10 | Dec 31 |
| 16°F | Feb 15 | Feb 2 | Jan 29 | Jan 25 | Jan 20 | Jan 15 | Jan 11 | Jan 6 | Dec 29 |
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 28 | Oct 31 | Nov 3 | Nov 5 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 25 |
| 32°F | Nov 4 | Nov 8 | Nov 13 | Nov 16 | Nov 20 | Nov 23 | Nov 28 | Dec 2 | Dec 10 |
| 28°F | Nov 14 | Nov 20 | Nov 26 | Dec 1 | Dec 5 | Dec 9 | Dec 17 | Dec 25 | Jan 3 |
| 24°F | Nov 29 | Dec 5 | Dec 13 | Dec 20 | Dec 25 | Dec 30 | Jan 4 | Jan 11 | Jan 19 |
| 20°F | Dec 10 | Dec 21 | Dec 26 | Dec 31 | Jan 5 | Jan 9 | Jan 15 | Jan 22 | Feb 1 |
| 16°F | Dec 21 | Dec 29 | Jan 3 | Jan 7 | Jan 11 | Jan 15 | Jan 21 | Jan 27 | Feb 3 |
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 | 252 | 243 | 236 | 231 | 226 | 222 | 217 | 211 | 204 |
| 32°F | 281 | 271 | 265 | 258 | 252 | 246 | 241 | 234 | 226 |
| 28°F | 314 | 303 | 295 | 287 | 281 | 275 | 268 | 261 | 252 |
| 24°F | 348 | 334 | 328 | 320 | 313 | 305 | 299 | 290 | 280 |
| 20°F | 365 | 363 | 354 | 345 | 339 | 333 | 326 | 316 | 303 |
| 16°F | 365 | 365 | 365 | 365 | 364 | 356 | 346 | 335 | 328 |
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
- 97% of years
- 20°F or colder
- 81% of years
- 16°F or colder
- 54% 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
- 2,531
- Cooling degree days, base 65°F
- 2,051
- Growing degree days, base 40°F
- 8,764
- Growing degree days, base 45°F
- 7,114
- Growing degree days, base 50°F
- 5,606
- Growing degree days, base 55°F
- 4,254
- Growing degree days, base 60°F
- 3,065
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 627 | 1 | 57 |
| February | 463 | 2 | 83 |
| March | 309 | 17 | 222 |
| April | 120 | 64 | 400 |
| May | 22 | 214 | 657 |
| June | 1 | 387 | 835 |
| July | 0 | 494 | 959 |
| August | 0 | 470 | 935 |
| September | 5 | 302 | 747 |
| October | 99 | 88 | 458 |
| November | 336 | 10 | 176 |
| December | 551 | 2 | 76 |
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 14.3 km from Gresham Park. 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 USW00013874 (Atlanta Hartsfield Intl AP). Public domain.