La Center Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Battle Ground. 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 26 and the first fall freeze around October 16, a growing season of about 174 days.
- Median at 36°F
- last May 13, first September 30
- Median at 32°F
- last April 26, first October 16
- Median at 28°F
- last March 29, first November 5
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 31 | May 26 | May 21 | May 17 | May 13 | May 10 | May 6 | May 3 | Apr 29 |
| 32°F | May 12 | May 5 | May 1 | Apr 29 | Apr 26 | Apr 23 | Apr 18 | Apr 13 | Apr 5 |
| 28°F | Apr 23 | Apr 15 | Apr 8 | Apr 2 | Mar 29 | Mar 25 | Mar 19 | Mar 13 | Mar 4 |
| 24°F | Mar 24 | Mar 13 | Mar 6 | Mar 1 | Feb 26 | Feb 22 | Feb 15 | Feb 5 | Jan 21 |
| 20°F | Feb 27 | Feb 22 | Feb 16 | Feb 7 | Jan 31 | Jan 20 | Jan 8 | Dec 31 | Dec 13 |
| 16°F | Feb 22 | Feb 12 | Feb 1 | Jan 24 | Jan 8 | Dec 31 | Dec 21 | Dec 11 | Dec 1 |
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 11 | Sep 18 | Sep 22 | Sep 26 | Sep 30 | Oct 3 | Oct 6 | Oct 11 | Oct 19 |
| 32°F | Sep 29 | Oct 5 | Oct 8 | Oct 13 | Oct 16 | Oct 21 | Oct 26 | Nov 1 | Nov 10 |
| 28°F | Oct 16 | Oct 21 | Oct 27 | Oct 31 | Nov 5 | Nov 10 | Nov 15 | Nov 21 | Nov 30 |
| 24°F | Oct 28 | Nov 5 | Nov 11 | Nov 18 | Nov 24 | Nov 30 | Dec 4 | Dec 13 | Dec 25 |
| 20°F | Nov 11 | Nov 23 | Nov 30 | Dec 5 | Dec 13 | Dec 22 | Dec 29 | Jan 6 | Jan 31 |
| 16°F | Nov 22 | Dec 1 | Dec 6 | Dec 14 | Dec 22 | Dec 29 | Jan 6 | Jan 25 | Feb 13 |
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 | 162 | 154 | 148 | 142 | 137 | 133 | 128 | 122 | 111 |
| 32°F | 203 | 191 | 185 | 179 | 174 | 168 | 162 | 156 | 148 |
| 28°F | 251 | 240 | 232 | 226 | 219 | 213 | 208 | 201 | 190 |
| 24°F | 314 | 299 | 289 | 279 | 273 | 265 | 257 | 245 | 235 |
| 20°F | 363 | 350 | 338 | 330 | 321 | 313 | 306 | 296 | 278 |
| 16°F | 365 | 365 | 365 | 365 | 364 | 352 | 340 | 332 | 316 |
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
- 89% of years
- 16°F or colder
- 49% 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
- 5,303
- Cooling degree days, base 65°F
- 164
- Growing degree days, base 40°F
- 4,273
- Growing degree days, base 45°F
- 2,907
- Growing degree days, base 50°F
- 1,839
- Growing degree days, base 55°F
- 1,036
- Growing degree days, base 60°F
- 480
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 806 | 0 | 2 |
| February | 671 | 0 | 2 |
| March | 631 | 0 | 15 |
| April | 486 | 0 | 50 |
| May | 318 | 5 | 171 |
| June | 191 | 17 | 277 |
| July | 74 | 61 | 453 |
| August | 66 | 63 | 462 |
| September | 166 | 17 | 303 |
| October | 428 | 1 | 92 |
| November | 645 | 0 | 12 |
| December | 821 | 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 14.9 km from La Center. 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 USC00450482 (Battle Ground). Public domain.