Entiat Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Entiat Fish Hatchery. 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 5 and the first fall freeze around October 24, a growing season of about 200 days.
- Median at 36°F
- last May 2, first October 12
- Median at 32°F
- last April 5, first October 24
- Median at 28°F
- last March 13, first November 7
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 3 | May 18 | May 11 | May 6 | May 2 | Apr 29 | Apr 25 | Apr 20 | Apr 14 |
| 32°F | May 2 | Apr 21 | Apr 13 | Apr 8 | Apr 5 | Apr 1 | Mar 30 | Mar 25 | Mar 17 |
| 28°F | Apr 4 | Mar 30 | Mar 25 | Mar 19 | Mar 13 | Mar 10 | Mar 6 | Mar 3 | Feb 26 |
| 24°F | Mar 19 | Mar 10 | Mar 6 | Mar 2 | Feb 28 | Feb 24 | Feb 20 | Feb 14 | Feb 7 |
| 20°F | Mar 9 | Mar 2 | Feb 27 | Feb 21 | Feb 16 | Feb 11 | Feb 6 | Jan 31 | Jan 17 |
| 16°F | Feb 28 | Feb 21 | Feb 14 | Feb 7 | Feb 2 | Jan 27 | Jan 18 | Jan 11 | Jan 2 |
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 16 | Sep 29 | Oct 3 | Oct 7 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 27 |
| 32°F | Sep 29 | Oct 10 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 31 | Nov 4 | Nov 10 |
| 28°F | Oct 17 | Oct 26 | Oct 31 | Nov 3 | Nov 7 | Nov 10 | Nov 15 | Nov 20 | Nov 25 |
| 24°F | Oct 31 | Nov 6 | Nov 10 | Nov 16 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 9 |
| 20°F | Nov 11 | Nov 19 | Nov 24 | Nov 28 | Dec 2 | Dec 6 | Dec 13 | Dec 21 | Jan 1 |
| 16°F | Nov 24 | Nov 30 | Dec 5 | Dec 10 | Dec 16 | Dec 21 | Dec 28 | Jan 3 | Jan 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 | 184 | 176 | 171 | 165 | 160 | 153 | 146 | 136 | 121 |
| 32°F | 227 | 217 | 211 | 205 | 200 | 195 | 186 | 176 | 157 |
| 28°F | 263 | 255 | 248 | 241 | 236 | 230 | 223 | 214 | 199 |
| 24°F | 294 | 285 | 276 | 270 | 265 | 260 | 254 | 246 | 235 |
| 20°F | 325 | 314 | 305 | 299 | 292 | 287 | 279 | 271 | 259 |
| 16°F | 354 | 341 | 332 | 325 | 318 | 311 | 304 | 295 | 282 |
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
- 96% 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
- 5,641
- Cooling degree days, base 65°F
- 690
- Growing degree days, base 40°F
- 5,054
- Growing degree days, base 45°F
- 3,841
- Growing degree days, base 50°F
- 2,800
- Growing degree days, base 55°F
- 1,931
- Growing degree days, base 60°F
- 1,224
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,080 | 0 | 0 |
| February | 822 | 0 | 0 |
| March | 660 | 0 | 13 |
| April | 415 | 1 | 91 |
| May | 207 | 29 | 294 |
| June | 78 | 87 | 459 |
| July | 14 | 254 | 705 |
| August | 15 | 241 | 691 |
| September | 97 | 75 | 428 |
| October | 412 | 3 | 114 |
| November | 776 | 0 | 4 |
| December | 1,065 | 0 | 0 |
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 8.9 km from Entiat. 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 USC00452563 (Entiat Fish Hatchery). Public domain.