Cypress Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Houston Hooks Mem 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 February 19 and the first fall freeze around December 3, a growing season of about 290 days.
- Median at 36°F
- last March 7, first November 19
- Median at 32°F
- last February 19, first December 3
- Median at 28°F
- last January 31, first December 29
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 29 | Mar 20 | Mar 15 | Mar 11 | Mar 7 | Mar 2 | Feb 26 | Feb 20 | Feb 11 |
| 32°F | Mar 15 | Mar 8 | Mar 1 | Feb 25 | Feb 19 | Feb 13 | Feb 4 | Jan 29 | Jan 21 |
| 28°F | Mar 5 | Feb 24 | Feb 14 | Feb 5 | Jan 31 | Jan 24 | Jan 17 | Jan 9 | Dec 28 |
| 24°F | Feb 23 | Feb 8 | Feb 2 | Jan 25 | Jan 17 | Jan 12 | Jan 7 | Jan 2 | Dec 24 |
| 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 2 | Nov 7 | Nov 11 | Nov 15 | Nov 19 | Nov 22 | Nov 27 | Dec 2 | Dec 8 |
| 32°F | Nov 13 | Nov 20 | Nov 25 | Nov 30 | Dec 3 | Dec 7 | Dec 15 | Dec 25 | Jan 5 |
| 28°F | Dec 2 | Dec 7 | Dec 15 | Dec 22 | Dec 29 | Jan 3 | Jan 8 | Jan 16 | Feb 1 |
| 24°F | Dec 11 | Dec 24 | Jan 1 | Jan 3 | Jan 6 | Jan 11 | Jan 17 | Jan 31 | Feb 6 |
| 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 | 289 | 278 | 270 | 264 | 258 | 251 | 245 | 238 | 228 |
| 32°F | 332 | 317 | 306 | 298 | 290 | 283 | 276 | 267 | 256 |
| 28°F | 365 | 359 | 349 | 340 | 333 | 324 | 314 | 303 | 289 |
| 24°F | 365 | 365 | 365 | 365 | 365 | 365 | 356 | 346 | 331 |
| 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
- 100% of years
- 32°F or colder
- 99% of years
- 28°F or colder
- 85% of years
- 24°F or colder
- 43% of years
- 20°F or colder
- 9% of years
- 16°F or colder
- 1% 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
- 1,368
- Cooling degree days, base 65°F
- 3,146
- Growing degree days, base 40°F
- 10,920
- Growing degree days, base 45°F
- 9,142
- Growing degree days, base 50°F
- 7,443
- Growing degree days, base 55°F
- 5,863
- Growing degree days, base 60°F
- 4,425
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 389 | 16 | 167 |
| February | 252 | 32 | 236 |
| March | 132 | 82 | 423 |
| April | 37 | 167 | 581 |
| May | 2 | 368 | 831 |
| June | 0 | 525 | 975 |
| July | 0 | 603 | 1,068 |
| August | 0 | 604 | 1,069 |
| September | 0 | 450 | 900 |
| October | 32 | 217 | 650 |
| November | 177 | 57 | 345 |
| December | 348 | 26 | 199 |
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 17.4 km from Cypress. 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 USW00053910 (Houston Hooks Mem AP). Public domain.