# Frost dates for O'Fallon, MO (63366)

**Do this (Safe, 2026-11-02):** Frost season started Oct 12. Keep covers ready for cold nights.

| Risk | Last spring frost | First fall frost | Frost-free days |
|---|---|---|---|
| Safe (1 in 10 years later) | Apr 26 | Oct 12 | 169 |
| Median | Apr 10 | Oct 26 | 199 |
| Bold (9 in 10 years later) | Mar 26 | Nov 8 | 227 |

Frost = 32°F. Station: Weldon Spring NWS, MO, 6 mi away.

## Next nights (NWS overnight low)

- 2026-11-01: 58°F — Go (tonight)
- 2026-11-02: 63°F — Go
- 2026-11-03: 52°F — Go
- 2026-11-04: 45°F — Go
- 2026-11-05: 43°F — Go
- 2026-11-06: 40°F — Wait
- 2026-11-07: 40°F — Wait

Go above 40°F · Wait 37–40°F · Cover 36°F or less · Freeze 28°F or less.

Source: Frost dates: NOAA NCEI U.S. Climate Normals 1991–2020, station Weldon Spring NWS, MO (6 mi, 75 ft higher than you). Not endorsed by NOAA. Nights: National Weather Service.

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