Frost Dates for Fitchburg, WI
In Fitchburg, WI, the average last spring frost is around May 1 and the average first fall frost around Oct 9, for a growing season of about 161 days. For frost-tender plants, wait until May 17, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the Uw Arboretum - Madison, WI weather station, 4 miles away, elevation 870 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 17 | Sep 26 |
| 20% | May 11 | Oct 1 |
| 30% | May 7 | Oct 3 |
| 40% | May 4 | Oct 6 |
| 50% | May 1 | Oct 9 |
| 60% | Apr 29 | Oct 12 |
| 70% | Apr 25 | Oct 15 |
| 80% | Apr 22 | Oct 18 |
| 90% | Apr 18 | Oct 24 |
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 13 | Oct 1 |
| Frost / freeze (32°F) | May 1 | Oct 9 |
| Hard freeze (28°F) | Apr 20 | Oct 20 |
Planting calendar for Fitchburg
Transplant May 8 – May 22
Transplant May 15 – May 29
Transplant May 15 – May 29
Transplant May 8 – May 22
Sow or transplant May 8 – May 22
Sow or transplant May 8 – May 22
Sow or transplant May 15 – May 29
Sow or transplant Apr 3 – Apr 17
Fall sowing Aug 14 – Sep 11
Fall sowing Aug 14 – Sep 4
Fall sowing Jul 31 – Aug 14
Sow or transplant Apr 3 – Apr 17
Fall sowing Jul 31 – Aug 28
Transplant Apr 17 – May 1
Fall sowing Jul 17 – Jul 31
Transplant Apr 10 – Apr 24
Fall sowing Jul 17 – Jul 31
Fall sowing Jul 17 – Jul 31
Fall sowing Aug 28 – Sep 18
Fall sowing Jul 31 – Aug 14
Plant Apr 3 – Apr 17
Based on the average last frost (May 1) and first frost (Oct 9). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.