ZIP 59102 Zone 5a
Montana · USDA zone 5a, average annual extreme minimum -20°F to -15°F.
Nearest qualified station: BILLINGS WFO, MT US (USC00240801), 1.8 miles from the Census ZCTA internal point for this ZIP.
Outside the median season Growing seasonTicks: 10%, 50%, and 90%
Last 32°F in spring
NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.
| Probability | Date | How to read it |
|---|---|---|
| 90% | April 23 | Earlier date. A last 32°F on or after this day is common. |
| 50% | May 5 | Median. |
| 10% | May 21 | Later date. A last 32°F on or after this day is uncommon. |
First 32°F in fall
NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.
| Probability | Date | How to read it |
|---|---|---|
| 10% | September 20 | Earlier date. A first 32°F on or before this day is uncommon. |
| 50% | October 3 | Median. |
| 90% | October 17 | Later date. A first 32°F on or before this day is common. |
32°F growing-season length
Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.
| Probability the season is at least this long | Days |
|---|---|
| 10% | 169 |
| 50% | 149 |
| 90% | 130 |
28°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | May 6 | April 23 | April 7 |
| First, on or before | September 29 | October 14 | October 27 |
| Season at least | 193 days | 172 days | 151 days |
36°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | June 2 | May 19 | May 6 |
| First, on or before | September 9 | September 23 | October 5 |
| Season at least | 144 days | 125 days | 107 days |
Station BILLINGS WFO, MT US (USC00240801). Completeness flag R, 21 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 970.8 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.