Sand Point Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Sand Point 1 Ene. 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 11 and the first fall freeze around October 18, a growing season of about 160 days.
- Median at 36°F
- last May 29, first October 3
- Median at 32°F
- last May 11, first October 18
- Median at 28°F
- last April 26, first November 1
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 10 | Jun 5 | Jun 2 | May 31 | May 29 | May 27 | May 23 | May 20 | May 14 |
| 32°F | May 25 | May 20 | May 17 | May 14 | May 11 | May 8 | May 5 | May 2 | Apr 26 |
| 28°F | May 12 | May 6 | May 3 | Apr 30 | Apr 26 | Apr 22 | Apr 18 | Apr 14 | Apr 10 |
| 24°F | Apr 30 | Apr 22 | Apr 17 | Apr 13 | Apr 11 | Apr 9 | Apr 5 | Apr 3 | Mar 31 |
| 20°F | Apr 19 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Apr 2 | Mar 30 | Mar 23 | Mar 13 |
| 16°F | Apr 10 | Apr 4 | Apr 1 | Mar 29 | Mar 22 | Mar 15 | Mar 2 | Feb 20 | Feb 4 |
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 24 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 18 |
| 32°F | Oct 4 | Oct 8 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 24 | Oct 30 | Nov 5 |
| 28°F | Oct 14 | Oct 20 | Oct 24 | Oct 28 | Nov 1 | Nov 5 | Nov 10 | Nov 15 | Nov 23 |
| 24°F | Oct 26 | Nov 1 | Nov 9 | Nov 14 | Nov 19 | Nov 23 | Nov 28 | Dec 2 | Dec 11 |
| 20°F | Nov 12 | Nov 20 | Nov 25 | Nov 30 | Dec 2 | Dec 8 | Dec 15 | Dec 23 | Jan 1 |
| 16°F | Nov 30 | Dec 6 | Dec 13 | Dec 19 | Dec 26 | Dec 31 | Jan 5 | Jan 15 | Jan 31 |
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 | 147 | 140 | 135 | 131 | 127 | 123 | 119 | 113 | 107 |
| 32°F | 185 | 176 | 170 | 164 | 160 | 155 | 152 | 147 | 140 |
| 28°F | 217 | 208 | 202 | 197 | 192 | 188 | 182 | 176 | 168 |
| 24°F | 247 | 237 | 231 | 225 | 220 | 214 | 208 | 202 | 194 |
| 20°F | 280 | 269 | 260 | 252 | 246 | 240 | 234 | 227 | 218 |
| 16°F | 327 | 308 | 296 | 284 | 276 | 271 | 264 | 255 | 244 |
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
- 9,127
- Cooling degree days, base 65°F
- 0
- Growing degree days, base 40°F
- 1,384
- Growing degree days, base 45°F
- 658
- Growing degree days, base 50°F
- 196
- Growing degree days, base 55°F
- 21
- Growing degree days, base 60°F
- 1
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,057 | 0 | 0 |
| February | 941 | 0 | 0 |
| March | 1,059 | 0 | 0 |
| April | 891 | 0 | 0 |
| May | 749 | 0 | 0 |
| June | 534 | 0 | 17 |
| July | 423 | 0 | 63 |
| August | 386 | 0 | 89 |
| September | 489 | 0 | 26 |
| October | 738 | 0 | 1 |
| November | 860 | 0 | 0 |
| December | 1,001 | 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 2.5 km from Sand Point. 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 USW00025630 (Sand Point 1 Ene). Public domain.