Battle Ground Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for W Lafayette 6 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 April 26 and the first fall freeze around October 12, a growing season of about 169 days.
- Median at 36°F
- last May 6, first September 30
- Median at 32°F
- last April 26, first October 12
- Median at 28°F
- last April 15, first October 25
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 15 | May 11 | May 9 | May 6 | May 3 | Apr 30 | Apr 27 | Apr 23 |
| 32°F | May 11 | May 6 | May 2 | Apr 30 | Apr 26 | Apr 23 | Apr 21 | Apr 17 | Apr 12 |
| 28°F | Apr 30 | Apr 25 | Apr 21 | Apr 18 | Apr 15 | Apr 12 | Apr 9 | Apr 6 | Apr 1 |
| 24°F | Apr 21 | Apr 15 | Apr 11 | Apr 7 | Apr 4 | Apr 1 | Mar 30 | Mar 24 | Mar 18 |
| 20°F | Apr 9 | Apr 3 | Mar 31 | Mar 28 | Mar 25 | Mar 21 | Mar 16 | Mar 13 | Mar 6 |
| 16°F | Mar 31 | Mar 26 | Mar 20 | Mar 16 | Mar 13 | Mar 10 | Mar 6 | Mar 2 | Feb 26 |
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 18 | Sep 22 | Sep 26 | Sep 28 | Sep 30 | Oct 3 | Oct 6 | Oct 9 | Oct 15 |
| 32°F | Sep 27 | Oct 1 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 19 | Oct 22 | Oct 27 |
| 28°F | Oct 8 | Oct 15 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 31 | Nov 2 | Nov 7 |
| 24°F | Oct 21 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 8 | Nov 11 | Nov 16 | Nov 22 |
| 20°F | Nov 3 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 21 | Nov 24 | Nov 30 | Dec 6 |
| 16°F | Nov 9 | Nov 15 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 5 | Dec 9 | Dec 17 |
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 | 167 | 160 | 155 | 151 | 147 | 143 | 139 | 135 | 128 |
| 32°F | 189 | 182 | 177 | 173 | 169 | 164 | 159 | 154 | 147 |
| 28°F | 211 | 205 | 200 | 194 | 190 | 186 | 181 | 175 | 168 |
| 24°F | 239 | 230 | 224 | 219 | 214 | 210 | 205 | 199 | 191 |
| 20°F | 264 | 256 | 249 | 244 | 240 | 235 | 230 | 224 | 216 |
| 16°F | 285 | 275 | 270 | 265 | 260 | 255 | 250 | 244 | 237 |
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
- 6,111
- Cooling degree days, base 65°F
- 826
- Growing degree days, base 40°F
- 5,356
- Growing degree days, base 45°F
- 4,190
- Growing degree days, base 50°F
- 3,154
- Growing degree days, base 55°F
- 2,242
- Growing degree days, base 60°F
- 1,463
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,260 | 0 | 1 |
| February | 1,032 | 0 | 3 |
| March | 825 | 2 | 35 |
| April | 451 | 9 | 127 |
| May | 178 | 71 | 371 |
| June | 27 | 194 | 617 |
| July | 7 | 247 | 705 |
| August | 14 | 196 | 648 |
| September | 104 | 92 | 442 |
| October | 388 | 15 | 169 |
| November | 734 | 1 | 33 |
| December | 1,091 | 0 | 4 |
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 13.2 km from Battle Ground. 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 USC00129430 (W Lafayette 6 Nw). Public domain.