Beulah Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Beulah 1 W. 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 21 and the first fall freeze around September 20, a growing season of about 121 days.
- Median at 36°F
- last May 31, first September 10
- Median at 32°F
- last May 21, first September 20
- Median at 28°F
- last May 11, first September 28
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 17 | Jun 9 | Jun 5 | Jun 2 | May 31 | May 28 | May 25 | May 22 | May 18 |
| 32°F | Jun 3 | May 30 | May 26 | May 24 | May 21 | May 18 | May 15 | May 12 | May 7 |
| 28°F | May 25 | May 20 | May 16 | May 13 | May 11 | May 7 | May 4 | May 1 | Apr 27 |
| 24°F | May 15 | May 10 | May 6 | May 3 | Apr 30 | Apr 28 | Apr 24 | Apr 19 | Apr 14 |
| 20°F | May 5 | Apr 30 | Apr 26 | Apr 23 | Apr 19 | Apr 16 | Apr 13 | Apr 10 | Apr 6 |
| 16°F | Apr 26 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 2 | Mar 27 |
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 | Aug 24 | Aug 31 | Sep 4 | Sep 7 | Sep 10 | Sep 13 | Sep 15 | Sep 19 | Sep 23 |
| 32°F | Sep 5 | Sep 10 | Sep 14 | Sep 17 | Sep 20 | Sep 22 | Sep 25 | Sep 29 | Oct 4 |
| 28°F | Sep 14 | Sep 19 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 4 | Oct 8 | Oct 14 |
| 24°F | Sep 22 | Sep 27 | Oct 1 | Oct 5 | Oct 8 | Oct 12 | Oct 16 | Oct 21 | Oct 28 |
| 20°F | Oct 1 | Oct 7 | Oct 12 | Oct 16 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 3 |
| 16°F | Oct 10 | Oct 17 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 10 |
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 | 121 | 114 | 109 | 105 | 100 | 96 | 91 | 84 | 74 |
| 32°F | 141 | 133 | 129 | 125 | 121 | 116 | 112 | 107 | 99 |
| 28°F | 163 | 155 | 150 | 145 | 142 | 137 | 133 | 127 | 120 |
| 24°F | 184 | 175 | 170 | 166 | 161 | 156 | 151 | 146 | 138 |
| 20°F | 202 | 195 | 190 | 186 | 182 | 176 | 172 | 166 | 158 |
| 16°F | 221 | 213 | 208 | 203 | 199 | 195 | 190 | 184 | 177 |
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
- 8,446
- Cooling degree days, base 65°F
- 529
- Growing degree days, base 40°F
- 4,179
- Growing degree days, base 45°F
- 3,201
- Growing degree days, base 50°F
- 2,338
- Growing degree days, base 55°F
- 1,595
- Growing degree days, base 60°F
- 985
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,610 | 0 | 0 |
| February | 1,316 | 0 | 0 |
| March | 1,071 | 0 | 4 |
| April | 640 | 1 | 48 |
| May | 323 | 16 | 209 |
| June | 98 | 75 | 429 |
| July | 27 | 201 | 638 |
| August | 36 | 186 | 616 |
| September | 191 | 49 | 324 |
| October | 609 | 3 | 67 |
| November | 1,068 | 0 | 3 |
| December | 1,458 | 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 1 km from Beulah. 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 USC00320766 (Beulah 1 W). Public domain.