Tampico Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Walnut. 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 April 24 and the first fall freeze around October 14, a growing season of about 172 days.
- Median at 36°F
- last May 3, first October 4
- Median at 32°F
- last April 24, first October 14
- Median at 28°F
- last April 12, first October 24
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 | May 20 | May 14 | May 10 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 20 |
| 32°F | May 9 | May 4 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 10 |
| 28°F | Apr 29 | Apr 22 | Apr 18 | Apr 15 | Apr 12 | Apr 9 | Apr 7 | Apr 4 | Mar 31 |
| 24°F | Apr 18 | Apr 12 | Apr 8 | Apr 5 | Apr 3 | Mar 31 | Mar 29 | Mar 23 | Mar 17 |
| 20°F | Apr 6 | Apr 2 | Mar 31 | Mar 27 | Mar 24 | Mar 20 | Mar 17 | Mar 12 | Mar 8 |
| 16°F | Mar 30 | Mar 24 | Mar 20 | Mar 17 | Mar 14 | Mar 11 | Mar 8 | Mar 4 | Feb 28 |
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 | Sep 21 | Sep 25 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 12 | Oct 16 |
| 32°F | Sep 30 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 27 |
| 28°F | Oct 11 | Oct 15 | Oct 19 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 24°F | Oct 20 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 17 |
| 20°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 29 |
| 16°F | Nov 7 | Nov 12 | Nov 16 | Nov 19 | Nov 22 | Nov 25 | Nov 29 | Dec 3 | Dec 9 |
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 | 169 | 164 | 159 | 155 | 152 | 148 | 144 | 139 | 132 |
| 32°F | 191 | 185 | 180 | 176 | 172 | 168 | 164 | 159 | 152 |
| 28°F | 212 | 204 | 200 | 196 | 193 | 189 | 185 | 179 | 172 |
| 24°F | 235 | 227 | 222 | 217 | 214 | 209 | 205 | 201 | 194 |
| 20°F | 257 | 250 | 244 | 240 | 235 | 230 | 225 | 220 | 213 |
| 16°F | 276 | 268 | 262 | 257 | 253 | 249 | 244 | 238 | 230 |
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
- 100% of years
- 20°F or colder
- 100% of years
- 16°F or colder
- 100% 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
- 6,510
- Cooling degree days, base 65°F
- 841
- Growing degree days, base 40°F
- 5,246
- Growing degree days, base 45°F
- 4,117
- Growing degree days, base 50°F
- 3,113
- Growing degree days, base 55°F
- 2,228
- Growing degree days, base 60°F
- 1,467
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,361 | 0 | 0 |
| February | 1,107 | 0 | 1 |
| March | 854 | 0 | 22 |
| April | 472 | 9 | 113 |
| May | 185 | 65 | 358 |
| June | 27 | 191 | 614 |
| July | 5 | 264 | 724 |
| August | 12 | 207 | 660 |
| September | 109 | 92 | 438 |
| October | 413 | 13 | 156 |
| November | 789 | 0 | 25 |
| December | 1,176 | 0 | 2 |
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 17.1 km from Tampico. 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 USC00118916 (Walnut). Public domain.