Frost dates in Altamont, SD
The average last spring frost in Altamont is around May 10 and the first fall frost is around September 30. That gives Altamont an average growing season of about 143 days.
Last spring frost
| Early (10% chance after) | April 22 |
|---|---|
| Average (50%) | May 10 |
| Late (90%) | May 22 |
First fall frost
| Early (10%) | September 19 |
|---|---|
| Average (50%) | September 30 |
| Late (90% chance before) | October 16 |