# Frost dates for Longmont, CO (80504)

**Do this (Safe, 2026-11-02):** Frost season started Sep 23. Keep covers ready for cold nights.

| Risk | Last spring frost | First fall frost | Frost-free days |
|---|---|---|---|
| Safe (1 in 10 years later) | May 22 | Sep 23 | 124 |
| Median | May 7 | Oct 5 | 151 |
| Bold (9 in 10 years later) | Apr 24 | Oct 16 | 175 |

Frost = 32°F. Station: Longmont 2 Ese, CO, 1 mi away.

## Next nights (NWS overnight low)

- 2026-11-01: 45°F — Go (tonight)
- 2026-11-02: 41°F — Go
- 2026-11-03: 34°F — Cover
- 2026-11-04: 36°F — Cover
- 2026-11-05: 34°F — Cover
- 2026-11-06: 36°F — Cover
- 2026-11-07: 32°F — Cover

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 Longmont 2 Ese, CO (1 mi, about your height). Not endorsed by NOAA. Nights: National Weather Service.

Page: https://frostdatecalculator.com/p/co/longmont · JSON: https://frostdatecalculator.com/p/co/longmont?format=json