Sidney Frost Dates and Growing Season
Frost and the growing season
NOAA's 1991-2020 freeze probabilities for Sidney. 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 September 27, a growing season of about 137 days.
- Median at 36°F
- last May 21, first September 18
- Median at 32°F
- last May 11, first September 27
- Median at 28°F
- last May 2, first October 6
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 30 | May 27 | May 24 | May 21 | May 18 | May 16 | May 13 | May 9 |
| 32°F | May 25 | May 20 | May 17 | May 14 | May 11 | May 8 | May 6 | May 3 | Apr 30 |
| 28°F | May 16 | May 11 | May 7 | May 5 | May 2 | Apr 30 | Apr 28 | Apr 24 | Apr 18 |
| 24°F | May 7 | May 2 | Apr 29 | Apr 26 | Apr 22 | Apr 19 | Apr 16 | Apr 12 | Apr 7 |
| 20°F | Apr 27 | Apr 22 | Apr 17 | Apr 14 | Apr 11 | Apr 8 | Apr 4 | Apr 1 | Mar 25 |
| 16°F | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 30 | Mar 26 | Mar 21 | Mar 14 |
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 4 | Sep 9 | Sep 13 | Sep 16 | Sep 18 | Sep 21 | Sep 23 | Sep 26 | Sep 30 |
| 32°F | Sep 13 | Sep 18 | Sep 22 | Sep 24 | Sep 27 | Sep 29 | Oct 1 | Oct 5 | Oct 9 |
| 28°F | Sep 22 | Sep 27 | Sep 30 | Oct 3 | Oct 6 | Oct 9 | Oct 13 | Oct 16 | Oct 20 |
| 24°F | Oct 1 | Oct 6 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 30 |
| 20°F | Oct 10 | Oct 15 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 4 | Nov 10 |
| 16°F | Oct 18 | Oct 23 | Oct 28 | Oct 31 | Nov 2 | Nov 6 | Nov 9 | Nov 14 | Nov 19 |
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 | 136 | 131 | 126 | 122 | 118 | 115 | 111 | 107 | 99 |
| 32°F | 154 | 147 | 144 | 140 | 137 | 133 | 129 | 124 | 117 |
| 28°F | 174 | 168 | 163 | 159 | 155 | 151 | 147 | 142 | 135 |
| 24°F | 197 | 190 | 184 | 180 | 175 | 172 | 167 | 162 | 155 |
| 20°F | 218 | 211 | 206 | 202 | 196 | 192 | 187 | 182 | 174 |
| 16°F | 235 | 228 | 223 | 218 | 214 | 211 | 206 | 200 | 192 |
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
- 7,770
- Cooling degree days, base 65°F
- 593
- Growing degree days, base 40°F
- 4,474
- Growing degree days, base 45°F
- 3,444
- Growing degree days, base 50°F
- 2,537
- Growing degree days, base 55°F
- 1,753
- Growing degree days, base 60°F
- 1,101
Growing degree days by month, base 50°F
Heating and cooling by month
| Month | Heating DD | Cooling DD | Growing DD 50 |
|---|---|---|---|
| January | 1,493 | 0 | 0 |
| February | 1,224 | 0 | 1 |
| March | 980 | 0 | 8 |
| April | 567 | 2 | 67 |
| May | 270 | 22 | 249 |
| June | 68 | 89 | 472 |
| July | 11 | 226 | 680 |
| August | 24 | 202 | 643 |
| September | 180 | 49 | 334 |
| October | 577 | 3 | 78 |
| November | 1,004 | 0 | 4 |
| December | 1,375 | 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 1.4 km from Sidney. 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 USC00247560 (Sidney). Public domain.