Frost Dates for Chicago, IL
In Chicago, IL, the average last spring frost is around Apr 10 and the average first fall frost around Nov 5, for a growing season of about 208 days. For frost-tender plants, wait until Apr 25, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Chicago Northerly Is, IL weather station, 4 miles away, elevation 583 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% | Apr 25 | Oct 24 |
| 20% | Apr 20 | Oct 28 |
| 30% | Apr 17 | Nov 1 |
| 40% | Apr 14 | Nov 2 |
| 50% | Apr 10 | Nov 5 |
| 60% | Apr 8 | Nov 8 |
| 70% | Apr 5 | Nov 11 |
| 80% | Apr 3 | Nov 14 |
| 90% | Mar 29 | Nov 20 |
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) | Apr 23 | Oct 26 |
| Frost / freeze (32°F) | Apr 10 | Nov 5 |
| Hard freeze (28°F) | Apr 1 | Nov 15 |
Planting calendar for Chicago
Transplant Apr 17 – May 1
Transplant Apr 24 – May 8
Transplant Apr 24 – May 8
Transplant Apr 17 – May 1
Sow or transplant Apr 17 – May 1
Sow or transplant Apr 17 – May 1
Sow or transplant Apr 24 – May 8
Sow or transplant Mar 13 – Mar 27
Fall sowing Sep 10 – Oct 8
Fall sowing Sep 10 – Oct 1
Fall sowing Aug 27 – Sep 10
Sow or transplant Mar 13 – Mar 27
Fall sowing Aug 27 – Sep 24
Transplant Mar 27 – Apr 10
Fall sowing Aug 13 – Aug 27
Transplant Mar 20 – Apr 3
Fall sowing Aug 13 – Aug 27
Fall sowing Aug 13 – Aug 27
Fall sowing Sep 24 – Oct 15
Fall sowing Aug 27 – Sep 10
Plant Mar 13 – Mar 27
Based on the average last frost (Apr 10) and first frost (Nov 5). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.