U.S. Frost Dates by Weather Station

NOAA station USC00051071 · Colorado

Frost Dates for Buena Vista, CO

NOAA weather station Buena Vista 2 S (USC00051071), Colorado · elevation 7954 ft (2424 m) · hardiness zone 5b*

  • Lower-risk planting dateafter June 11only 1 spring in 10 still has a frost later
  • Typical last frostMay 2750% chance of a frost after it
  • Typical first fall frostSeptember 2350% chance of a frost before it
  • Frost-free season116 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Buena Vista, COSpring: a frost after May 13 in 9 years out of 10, after May 27 in half of the years, after June 11 in 1 year out of 10. Fall: the first frost comes before September 10 in 1 year out of 10, before September 23 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 116 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 27First frost ~Sep 23Frost season at Buena Vista, COSpring: a frost after May 13 in 9 years out of 10, after May 27 in half of the years, after June 11 in 1 year out of 10. Fall: the first frost comes before September 10 in 1 year out of 10, before September 23 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 116 days.JFMAMJJASONDLast frost ~May 27First frost ~Sep 23
frost likely chance fading 90% → 10% frost-free in a typical yearThe year at a glance. Blue: frost is likely; the gradient fades as the chance drops from 90% to 10%; green: the frost-free part of a typical year.

Frost dates (32°F)

Probability of frost, based on 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 11September 10
50% (typical)May 27September 23
90% (likely)May 13October 4
Frost-free season (32°F, 50% chance)
116 days
Hard frost (28°F), last in spring, 50% chance after
May 15
Hard frost (28°F), first in fall, 50% chance before
October 2

The last 15 years (2006–2020 normals)

Typical last frost May 25 (2 days earlier than the 30-year normal), typical first fall frost September 27 (4 days later). Frost-free season 124 days.

A shorter, more recent NOAA period. The 30-year normals above remain the main reference: 15 years carry more year-to-year noise.

Add these dates to your calendar Yearly reminders for the typical last frost, the lower-risk planting date and the typical first fall frost (.ics).

How the chance of frost changes with the date

Spring at Buena Vista: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 11, 20% June 6, 30% June 2, 40% May 31, 50% May 27, 60% May 24, 70% May 21, 80% May 17, 90% May 13. Observed last spring frost in recent years: 2021 May 24, 2022 May 31, 2023 May 6, 2024 May 22, 2025 May 20, 2026 May 21.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 11May 27May 132021: May 242022: May 312023: May 62024: May 222025: May 202026: May 21Fall at Buena Vista: chance of a frost before this dateFall, chance of a frost before the date: 10% September 10, 20% September 15, 30% September 18, 40% September 20, 50% September 23, 60% September 25, 70% September 27, 80% September 30, 90% October 4. Observed first fall frost in recent years: 2021 September 21, 2022 October 8, 2023 October 6, 2024 October 16, 2025 October 5.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 10Sep 23Oct 42021: September 212022: October 82023: October 62024: October 162025: October 5
Two charts, because spring and fall answer different questions: in spring, the chance that a frost still comes after a date; in fall, the chance that the first frost has already come before it. NOAA publishes these odds from 10% to 90%, so the lines stop there. ◆ marks the actual date in each recent year.

What actually happened in recent years

Observed dates of the last spring and first fall frost (32°F) at this station; ◆ marks them on the charts above
YearLast spring frostFirst fall frost
2021May 24September 21
2022May 31October 8
2023May 6October 6
2024May 22October 16
2025May 20October 5
2026May 21season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Buena Vista is September 10, when there is only a 10% chance that a light frost has arrived.

The cautious spring date for setting out tender crops is June 11, which carries a 10% chance of a light frost occurring later; planting before the May 13 date would be a gamble with a 90% chance of frost later. The median light-frost dates are May 27 in spring and September 23 in fall; each represents a 50% chance of a frost occurring on either side of the date. The hard-frost median dates are May 15 and October 2, and a hard frost at 28 °F can damage plants more severely than a light frost at 32 °F.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after June 11" means that in about one spring out of ten a frost still happens after that date. The 90% date is the earliest: a frost after it happens in most years.
  • Fall: "10% before September 10" means that in about one fall out of ten the first frost arrives before that date.
  • 50% is the typical date: half of the years are earlier, half are later.
  • A light frost (32°F) damages tender plants; a hard frost (28°F) also stops most hardy vegetables.

Nearby weather stations

Map of weather stations near Buena Vista, CONumbered nearest stations: 1 — Taylor Park, CO — 26 mi; 2 — Lake George 8 SW, CO — 36 mi; 3 — Cochetopa Creek, CO — 43 mi; 4 — Grant, CO — 50 mi; 5 — Bailey, CO — 53 mi.25 mi · 40 km1. Taylor Park, CO — 26 mi12. Lake George 8 SW, CO — 36 mi23. Cochetopa Creek, CO — 43 mi34. Grant, CO — 50 mi45. Bailey, CO — 53 mi5
  1. Taylor Park, CO 26 mi (42 km)
  2. Lake George 8 SW, CO 36 mi (58 km)
  3. Cochetopa Creek, CO 43 mi (70 km)
  4. Grant, CO 50 mi (81 km)
  5. Bailey, CO 53 mi (86 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 38.8247, -106.1275.