Orleans Parish Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for New Orleans Lakefront 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 January 22 and the first fall freeze around January 5, a growing season of about 348 days.
- Median at 36°F
- last February 4, first December 26
- Median at 32°F
- last January 22, first January 5
- Median at 28°F
- last January 18, first January 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 | Mar 7 | Feb 27 | Feb 17 | Feb 10 | Feb 4 | Jan 30 | Jan 24 | Jan 17 | Jan 5 |
| 32°F | Feb 23 | Feb 9 | Feb 1 | Jan 27 | Jan 22 | Jan 17 | Jan 12 | Jan 5 | Dec 28 |
| 28°F | Feb 11 | Feb 1 | Jan 28 | Jan 23 | Jan 18 | Jan 14 | Jan 9 | Jan 3 | Dec 26 |
| 24°F | – | – | – | – | – | – | – | – | – |
| 20°F | – | – | – | – | – | – | – | – | – |
| 16°F | – | – | – | – | – | – | – | – | – |
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 | Nov 30 | Dec 8 | Dec 15 | Dec 21 | Dec 26 | Dec 31 | Jan 4 | Jan 10 | Jan 19 |
| 32°F | Dec 13 | Dec 23 | Dec 29 | Jan 1 | Jan 5 | Jan 9 | Jan 15 | Jan 20 | Feb 1 |
| 28°F | Dec 23 | Dec 31 | Jan 3 | Jan 7 | Jan 11 | Jan 15 | Jan 19 | Jan 26 | Feb 4 |
| 24°F | – | – | – | – | – | – | – | – | – |
| 20°F | – | – | – | – | – | – | – | – | – |
| 16°F | – | – | – | – | – | – | – | – | – |
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 | 356 | 343 | 335 | 329 | 321 | 312 | 305 | 297 | 286 |
| 32°F | 365 | 365 | 363 | 356 | 348 | 341 | 335 | 326 | 310 |
| 28°F | 365 | 365 | 365 | 365 | 365 | 365 | 363 | 352 | 339 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
| 20°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
| 16°F | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 | 365 |
How often it gets that cold
The share of years with at least one night at or below each temperature.
- 36°F or colder
- 95% of years
- 32°F or colder
- 71% of years
- 28°F or colder
- 34% of years
- 24°F or colder
- 9% of years
- 20°F or colder
- 2% of years
- 16°F or colder
- 0% 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
- 1,134
- Cooling degree days, base 65°F
- 3,292
- Growing degree days, base 40°F
- 11,294
- Growing degree days, base 45°F
- 9,499
- Growing degree days, base 50°F
- 7,759
- Growing degree days, base 55°F
- 6,120
- Growing degree days, base 60°F
- 4,625
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 356 | 14 | 182 |
| February | 222 | 27 | 248 |
| March | 106 | 78 | 442 |
| April | 22 | 188 | 617 |
| May | 1 | 396 | 860 |
| June | 0 | 535 | 985 |
| July | 0 | 601 | 1,066 |
| August | 0 | 611 | 1,076 |
| September | 0 | 492 | 942 |
| October | 15 | 260 | 710 |
| November | 127 | 69 | 397 |
| December | 286 | 21 | 233 |
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 10 km from Orleans Parish. 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 USW00053917 (New Orleans Lakefront AP). Public domain.