Frost Dates for Portage, IN
In Portage, IN, the average last spring frost is around Apr 22 and the average first fall frost around Oct 27, for a growing season of about 188 days. For frost-tender plants, wait until May 8, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Indiana Dunes Nl, IN weather station, 5 miles away, elevation 680 ft. Frost can come earlier in low spots and valleys and later near cities and large lakes.
Frost probability by date
Chance of a 32°F frost after the spring date, or before the fall date.
| Chance | Last spring frost | First fall frost |
|---|---|---|
| 10% | May 8 | Oct 15 |
| 20% | May 2 | Oct 20 |
| 30% | Apr 29 | Oct 22 |
| 40% | Apr 25 | Oct 25 |
| 50% | Apr 22 | Oct 27 |
| 60% | Apr 19 | Oct 30 |
| 70% | Apr 16 | Nov 1 |
| 80% | Apr 12 | Nov 4 |
| 90% | Apr 7 | Nov 9 |
Light frost vs. hard freeze
Average (50%) dates for each temperature. Tender plants are damaged at 36°F; most hardy crops survive until 28°F.
| Temperature | Last in spring | First in fall |
|---|---|---|
| Light frost (36°F) | May 4 | Oct 16 |
| Frost / freeze (32°F) | Apr 22 | Oct 27 |
| Hard freeze (28°F) | Apr 8 | Nov 7 |
Planting calendar for Portage
Transplant Apr 29 – May 13
Transplant May 6 – May 20
Transplant May 6 – May 20
Transplant Apr 29 – May 13
Sow or transplant Apr 29 – May 13
Sow or transplant Apr 29 – May 13
Sow or transplant May 6 – May 20
Sow or transplant Mar 25 – Apr 8
Fall sowing Sep 1 – Sep 29
Fall sowing Sep 1 – Sep 22
Fall sowing Aug 18 – Sep 1
Sow or transplant Mar 25 – Apr 8
Fall sowing Aug 18 – Sep 15
Transplant Apr 8 – Apr 22
Fall sowing Aug 4 – Aug 18
Transplant Apr 1 – Apr 15
Fall sowing Aug 4 – Aug 18
Fall sowing Aug 4 – Aug 18
Fall sowing Sep 15 – Oct 6
Fall sowing Aug 18 – Sep 1
Plant Mar 25 – Apr 8
Based on the average last frost (Apr 22) and first frost (Oct 27). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.