Here is a chart showing the average growing season length in days. by your hardiness zones.
It is based on the last spring frost to first fall frost dates
| USDA Zone | Last Frost (Approx.) | First Frost (Approx.) | Growing Season (Days) |
| 3 | May 15 – May 31 | Sep 1 – Sep 15 | ~90–120 days |
| 4 | May 1 – May 15 | Sep 15 – Oct 1 | ~120–150 days |
| 5 | Apr 15 – May 1 | Oct 1 – Oct 15 | ~150–180 days |
| 6 | Apr 1 – Apr 15 | Oct 15 – Oct 30 | ~170–200 days |
| 7 | Mar 15 – Apr 1 | Oct 30 – Nov 15 | ~180–220 days |
| 8 | Mar 1 – Mar 15 | Nov 15 – Dec 1 | ~210–240 days |
| 9 | Feb 15 – Mar 1 | Dec 1 – Dec 15 | ~240–270 days |
| 10 | Jan 31 – Feb 15 | Dec 15 – Jan 15 (next year) | ~270–300 days |
| 11 | Frost-Free | Frost-Free | Year-round growing |
Notes:
These are averages—local microclimates and elevation can shift dates.
You can use these to decide when to plant frost-sensitive crops like tomatoes and peppers.
For Zones 9–11, the heat, not frost, becomes the limiting factor in summer.