Frost Dates for Joliet, IL
In Joliet, IL, the average last spring frost is around Apr 19 and the average first fall frost around Oct 25, for a growing season of about 188 days. For frost-tender plants, wait until May 7, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Joliet Brandon Rd Dam, IL weather station, 2 miles away, elevation 543 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 7 | Oct 12 |
| 20% | Apr 30 | Oct 17 |
| 30% | Apr 26 | Oct 20 |
| 40% | Apr 22 | Oct 23 |
| 50% | Apr 19 | Oct 25 |
| 60% | Apr 16 | Oct 27 |
| 70% | Apr 12 | Oct 30 |
| 80% | Apr 9 | Nov 1 |
| 90% | Apr 3 | Nov 6 |
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 1 | Oct 15 |
| Frost / freeze (32°F) | Apr 19 | Oct 25 |
| Hard freeze (28°F) | Apr 5 | Nov 4 |
Planting calendar for Joliet
Transplant Apr 26 – May 10
Transplant May 3 – May 17
Transplant May 3 – May 17
Transplant Apr 26 – May 10
Sow or transplant Apr 26 – May 10
Sow or transplant Apr 26 – May 10
Sow or transplant May 3 – May 17
Sow or transplant Mar 22 – Apr 5
Fall sowing Aug 30 – Sep 27
Fall sowing Aug 30 – Sep 20
Fall sowing Aug 16 – Aug 30
Sow or transplant Mar 22 – Apr 5
Fall sowing Aug 16 – Sep 13
Transplant Apr 5 – Apr 19
Fall sowing Aug 2 – Aug 16
Transplant Mar 29 – Apr 12
Fall sowing Aug 2 – Aug 16
Fall sowing Aug 2 – Aug 16
Fall sowing Sep 13 – Oct 4
Fall sowing Aug 16 – Aug 30
Plant Mar 22 – Apr 5
Based on the average last frost (Apr 19) and first frost (Oct 25). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.