Walsenburg Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Walsenburg 1 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 May 6 and the first fall freeze around October 4, a growing season of about 149 days.
- Median at 36°F
- last May 18, first September 28
- Median at 32°F
- last May 6, first October 4
- Median at 28°F
- last April 29, first October 15
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 | Jun 1 | May 28 | May 24 | May 21 | May 18 | May 15 | May 12 | May 9 | May 5 |
| 32°F | May 20 | May 15 | May 11 | May 8 | May 6 | May 4 | May 2 | Apr 29 | Apr 24 |
| 28°F | May 9 | May 5 | May 3 | May 1 | Apr 29 | Apr 26 | Apr 23 | Apr 19 | Apr 14 |
| 24°F | May 2 | Apr 27 | Apr 24 | Apr 20 | Apr 18 | Apr 15 | Apr 12 | Apr 8 | Apr 3 |
| 20°F | Apr 22 | Apr 18 | Apr 14 | Apr 10 | Apr 6 | Apr 3 | Mar 31 | Mar 25 | Mar 19 |
| 16°F | Apr 13 | Apr 6 | Apr 3 | Mar 30 | Mar 25 | Mar 22 | Mar 17 | Mar 11 | Mar 3 |
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 15 | Sep 19 | Sep 23 | Sep 26 | Sep 28 | Sep 30 | Oct 2 | Oct 5 | Oct 9 |
| 32°F | Sep 23 | Sep 27 | Sep 30 | Oct 2 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 17 |
| 28°F | Oct 1 | Oct 5 | Oct 8 | Oct 11 | Oct 15 | Oct 17 | Oct 20 | Oct 23 | Oct 28 |
| 24°F | Oct 9 | Oct 14 | Oct 17 | Oct 21 | Oct 23 | Oct 27 | Oct 30 | Nov 2 | Nov 6 |
| 20°F | Oct 17 | Oct 22 | Oct 27 | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 12 | Nov 18 |
| 16°F | Oct 24 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 14 | Nov 18 | Nov 23 | Nov 27 |
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 | 148 | 142 | 138 | 134 | 131 | 128 | 123 | 119 | 112 |
| 32°F | 168 | 161 | 156 | 152 | 149 | 146 | 141 | 137 | 131 |
| 28°F | 187 | 180 | 176 | 172 | 168 | 165 | 161 | 156 | 149 |
| 24°F | 208 | 201 | 196 | 191 | 187 | 183 | 179 | 174 | 168 |
| 20°F | 233 | 225 | 218 | 212 | 207 | 203 | 198 | 193 | 186 |
| 16°F | 256 | 246 | 239 | 233 | 227 | 222 | 216 | 209 | 201 |
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
- 5,463
- Cooling degree days, base 65°F
- 623
- Growing degree days, base 40°F
- 5,207
- Growing degree days, base 45°F
- 3,942
- Growing degree days, base 50°F
- 2,857
- Growing degree days, base 55°F
- 1,946
- Growing degree days, base 60°F
- 1,202
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 961 | 0 | 3 |
| February | 829 | 0 | 6 |
| March | 708 | 0 | 30 |
| April | 496 | 1 | 85 |
| May | 247 | 17 | 264 |
| June | 42 | 121 | 530 |
| July | 4 | 235 | 696 |
| August | 10 | 185 | 640 |
| September | 102 | 60 | 412 |
| October | 390 | 3 | 154 |
| November | 696 | 0 | 34 |
| December | 978 | 0 | 3 |
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 1.5 km from Walsenburg. 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 USC00058781 (Walsenburg 1 Nw). Public domain.