Frost dates in Alton, MO
The average last spring frost in Alton is around April 16 and the first fall frost is around October 17. That gives Alton an average growing season of about 184 days.
Last spring frost
| Early (10% chance after) | April 5 |
|---|---|
| Average (50%) | April 16 |
| Late (90%) | May 3 |
First fall frost
| Early (10%) | October 3 |
|---|---|
| Average (50%) | October 17 |
| Late (90% chance before) | October 30 |