Lago Vista Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Austin 33 Nw. 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 2 and the first fall freeze around November 29, a growing season of about 274 days.
- Median at 36°F
- last March 14, first November 18
- Median at 32°F
- last March 2, first November 29
- Median at 28°F
- last February 16, first December 13
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 5 | Mar 29 | Mar 23 | Mar 18 | Mar 14 | Mar 11 | Mar 7 | Mar 2 | Feb 25 |
| 32°F | Mar 20 | Mar 14 | Mar 9 | Mar 5 | Mar 2 | Feb 28 | Feb 23 | Feb 16 | Feb 6 |
| 28°F | Mar 11 | Mar 4 | Feb 28 | Feb 22 | Feb 16 | Feb 9 | Feb 1 | Jan 25 | Jan 12 |
| 24°F | Mar 2 | Feb 21 | Feb 13 | Feb 5 | Jan 29 | Jan 21 | Jan 12 | Jan 1 | Dec 20 |
| 20°F | Feb 22 | Feb 11 | Feb 2 | Jan 22 | Jan 15 | Jan 7 | Jan 3 | Dec 31 | Dec 22 |
| 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 10 | Nov 15 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 5 |
| 32°F | Nov 10 | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 19 |
| 28°F | Nov 20 | Nov 29 | Dec 4 | Dec 9 | Dec 13 | Dec 19 | Dec 25 | Jan 1 | Jan 16 |
| 24°F | Dec 4 | Dec 12 | Dec 18 | Dec 23 | Dec 30 | Jan 4 | Jan 13 | Jan 24 | Feb 10 |
| 20°F | Dec 15 | Dec 23 | Dec 30 | Jan 3 | Jan 6 | Jan 15 | Jan 24 | Feb 3 | Feb 14 |
| 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 | 273 | 264 | 258 | 253 | 249 | 243 | 238 | 232 | 223 |
| 32°F | 304 | 294 | 286 | 280 | 274 | 267 | 261 | 254 | 245 |
| 28°F | 342 | 330 | 320 | 311 | 304 | 298 | 290 | 282 | 271 |
| 24°F | 365 | 365 | 358 | 348 | 339 | 330 | 321 | 311 | 300 |
| 20°F | 365 | 365 | 365 | 365 | 365 | 365 | 361 | 347 | 327 |
| 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
- 100% of years
- 28°F or colder
- 98% of years
- 24°F or colder
- 77% of years
- 20°F or colder
- 35% of years
- 16°F or colder
- 10% 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
- 1,786
- Cooling degree days, base 65°F
- 2,695
- Growing degree days, base 40°F
- 10,098
- Growing degree days, base 45°F
- 8,373
- Growing degree days, base 50°F
- 6,738
- Growing degree days, base 55°F
- 5,236
- Growing degree days, base 60°F
- 3,882
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 463 | 6 | 122 |
| February | 350 | 13 | 163 |
| March | 192 | 44 | 339 |
| April | 53 | 118 | 515 |
| May | 8 | 286 | 743 |
| June | 0 | 469 | 919 |
| July | 0 | 569 | 1,034 |
| August | 0 | 585 | 1,050 |
| September | 2 | 383 | 831 |
| October | 49 | 183 | 602 |
| November | 226 | 34 | 288 |
| December | 442 | 6 | 133 |
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 20.3 km from Lago Vista. 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 USW00023907 (Austin 33 Nw). Public domain.