When to plant Summer squash (zucchini) in Montana
In spring, from May 1 – 30 in Billings to June 10 – 20 in Butte-Silver Bow (balance).
In fall, from May 15 – July 1 in Belgrade to June 1 – July 1 in Missoula.
USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.
| Place | Spring | Fall |
|---|---|---|
| Belgrade | June 1 – 20 | May 15 – July 1 |
| Billings | May 1 – 30 | June 1 – July 15 |
| Bozeman | June 1 – 20 | May 15 – July 1 |
| Butte-Silver Bow (balance) | June 10 – 20 | June 1 – 20 |
| Great Falls | May 10 – June 10 | June 1 – July 1 |
| Helena | May 10 – June 10 | June 1 – July 1 |
| Kalispell | June 1 – 20 | June 1 – 20 |
| Missoula | May 10 – June 10 | June 1 – July 1 |
Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. “—” means the place's frost date is outside the table. The full USDA table for summer squash.