Frost Dates for Florissant, MO
In Florissant, MO, the average last spring frost is around Apr 2 and the average first fall frost around Nov 4, for a growing season of about 215 days. For frost-tender plants, wait until Apr 17, when the chance of frost drops to 10%.
Based on NOAA 1991–2020 records from the St Louis Lambert Intl. Airport, MO weather station, 4 miles away, elevation 531 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 17 | Oct 23 |
| 20% | Apr 11 | Oct 27 |
| 30% | Apr 7 | Oct 30 |
| 40% | Apr 5 | Nov 1 |
| 50% | Apr 2 | Nov 4 |
| 60% | Mar 31 | Nov 6 |
| 70% | Mar 28 | Nov 9 |
| 80% | Mar 24 | Nov 12 |
| 90% | Mar 17 | Nov 18 |
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 13 | Oct 26 |
| Frost / freeze (32°F) | Apr 2 | Nov 4 |
| Hard freeze (28°F) | Mar 23 | Nov 13 |
Planting calendar for Florissant
Transplant Apr 9 – Apr 23
Transplant Apr 16 – Apr 30
Transplant Apr 16 – Apr 30
Transplant Apr 9 – Apr 23
Sow or transplant Apr 9 – Apr 23
Sow or transplant Apr 9 – Apr 23
Sow or transplant Apr 16 – Apr 30
Sow or transplant Mar 5 – Mar 19
Fall sowing Sep 9 – Oct 7
Fall sowing Sep 9 – Sep 30
Fall sowing Aug 26 – Sep 9
Sow or transplant Mar 5 – Mar 19
Fall sowing Aug 26 – Sep 23
Transplant Mar 19 – Apr 2
Fall sowing Aug 12 – Aug 26
Transplant Mar 12 – Mar 26
Fall sowing Aug 12 – Aug 26
Fall sowing Aug 12 – Aug 26
Fall sowing Sep 23 – Oct 14
Fall sowing Aug 26 – Sep 9
Plant Mar 5 – Mar 19
Based on the average last frost (Apr 2) and first frost (Nov 4). The dashed lines mark those dates. Seed packets list days to maturity; adjust for your varieties.