Everett Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Everett. 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 27 and the first fall freeze around October 17, a growing season of about 170 days.
- Median at 36°F
- last May 9, first October 6
- Median at 32°F
- last April 27, first October 17
- Median at 28°F
- last April 12, first October 29
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 27 | May 21 | May 17 | May 13 | May 9 | May 5 | Apr 30 | Apr 28 | Apr 23 |
| 32°F | May 16 | May 9 | May 4 | Apr 30 | Apr 27 | Apr 23 | Apr 20 | Apr 17 | Apr 12 |
| 28°F | May 1 | Apr 23 | Apr 19 | Apr 16 | Apr 12 | Apr 9 | Apr 7 | Apr 3 | Mar 30 |
| 24°F | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 29 | Mar 26 | Mar 21 | Mar 15 |
| 20°F | Apr 1 | Mar 30 | Mar 26 | Mar 22 | Mar 19 | Mar 16 | Mar 13 | Mar 8 | Mar 2 |
| 16°F | Mar 23 | Mar 18 | Mar 15 | Mar 12 | Mar 8 | Mar 5 | Mar 1 | Feb 26 | Feb 19 |
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 23 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 15 | Oct 20 |
| 32°F | Oct 3 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 26 | Nov 1 |
| 28°F | Oct 11 | Oct 18 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 10 |
| 24°F | Oct 25 | Oct 30 | Nov 2 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 24 |
| 20°F | Nov 5 | Nov 10 | Nov 15 | Nov 18 | Nov 21 | Nov 24 | Nov 28 | Dec 2 | Dec 10 |
| 16°F | Nov 18 | Nov 25 | Nov 30 | Dec 2 | Dec 7 | Dec 11 | Dec 17 | Dec 22 | Dec 29 |
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 | 162 | 157 | 152 | 148 | 143 | 139 | 133 | 126 |
| 32°F | 192 | 185 | 180 | 175 | 170 | 166 | 161 | 155 | 147 |
| 28°F | 217 | 211 | 206 | 202 | 197 | 192 | 188 | 181 | 171 |
| 24°F | 244 | 237 | 230 | 227 | 223 | 219 | 214 | 208 | 201 |
| 20°F | 272 | 263 | 258 | 254 | 249 | 243 | 239 | 234 | 225 |
| 16°F | 302 | 293 | 288 | 282 | 276 | 272 | 266 | 261 | 252 |
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
- 5,621
- Cooling degree days, base 65°F
- 745
- Growing degree days, base 40°F
- 5,288
- Growing degree days, base 45°F
- 4,079
- Growing degree days, base 50°F
- 3,021
- Growing degree days, base 55°F
- 2,115
- Growing degree days, base 60°F
- 1,355
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,097 | 0 | 2 |
| February | 925 | 0 | 3 |
| March | 791 | 1 | 24 |
| April | 444 | 6 | 115 |
| May | 197 | 45 | 324 |
| June | 40 | 145 | 555 |
| July | 5 | 249 | 710 |
| August | 9 | 209 | 665 |
| September | 96 | 81 | 437 |
| October | 383 | 10 | 153 |
| November | 677 | 0 | 28 |
| December | 958 | 0 | 5 |
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 0.7 km from Everett. 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 USC00362721 (Everett). Public domain.