Henderson Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Las Vegas Mccarran 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 20 and the first fall freeze around December 15, a growing season of about 333 days.
- Median at 36°F
- last February 11, first December 3
- Median at 32°F
- last January 20, first December 15
- Median at 28°F
- last December 31, first December 26
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 4 | Feb 26 | Feb 21 | Feb 16 | Feb 11 | Feb 6 | Feb 2 | Jan 29 | Jan 19 |
| 32°F | Feb 14 | Feb 6 | Feb 1 | Jan 26 | Jan 20 | Jan 14 | Jan 7 | Dec 31 | Dec 20 |
| 28°F | Jan 29 | Jan 17 | Jan 9 | Jan 5 | Dec 31 | Dec 29 | Dec 23 | Dec 17 | Dec 10 |
| 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 18 | Nov 23 | Nov 26 | Nov 30 | Dec 3 | Dec 5 | Dec 8 | Dec 12 | Dec 17 |
| 32°F | Nov 28 | Dec 4 | Dec 8 | Dec 12 | Dec 15 | Dec 19 | Dec 23 | Dec 29 | Jan 7 |
| 28°F | Dec 6 | Dec 11 | Dec 16 | Dec 22 | Dec 26 | Dec 30 | Jan 1 | Jan 8 | Jan 22 |
| 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 | 323 | 313 | 305 | 298 | 293 | 287 | 283 | 275 | 268 |
| 32°F | 360 | 351 | 343 | 338 | 333 | 327 | 318 | 310 | 299 |
| 28°F | 365 | 365 | 365 | 365 | 365 | 361 | 355 | 347 | 335 |
| 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
- 100% of years
- 32°F or colder
- 94% of years
- 28°F or colder
- 45% of years
- 24°F or colder
- 7% of years
- 20°F or colder
- 0% 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
- 1,836
- Cooling degree days, base 65°F
- 3,720
- Growing degree days, base 40°F
- 11,018
- Growing degree days, base 45°F
- 9,244
- Growing degree days, base 50°F
- 7,587
- Growing degree days, base 55°F
- 6,114
- Growing degree days, base 60°F
- 4,837
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 481 | 0 | 59 |
| February | 323 | 1 | 130 |
| March | 166 | 36 | 340 |
| April | 55 | 136 | 531 |
| May | 8 | 390 | 846 |
| June | 1 | 679 | 1,128 |
| July | 0 | 876 | 1,341 |
| August | 0 | 828 | 1,293 |
| September | 0 | 560 | 1,010 |
| October | 33 | 200 | 633 |
| November | 250 | 16 | 234 |
| December | 519 | 0 | 43 |
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 16.7 km from Henderson. 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 USW00023169 (Las Vegas Mccarran AP). Public domain.