U.S. Frost Dates by Weather Station

NOAA station USC00291664 · New Mexico

Frost Dates for Chama, NM

NOAA weather station Chama (USC00291664), New Mexico · elevation 7850 ft (2393 m) · hardiness zone 5a*

  • Lower-risk planting dateafter June 30only 1 spring in 10 still has a frost later
  • Typical last frostJune 1450% chance of a frost after it
  • Typical first fall frostSeptember 1850% chance of a frost before it
  • Frost-free season93 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Chama, NMSpring: a frost after June 1 in 9 years out of 10, after June 14 in half of the years, after June 30 in 1 year out of 10. Fall: the first frost comes before September 7 in 1 year out of 10, before September 18 in half of the years, before September 29 in 9 years out of 10. Typical frost-free season: 93 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Jun 14First frost ~Sep 18Frost season at Chama, NMSpring: a frost after June 1 in 9 years out of 10, after June 14 in half of the years, after June 30 in 1 year out of 10. Fall: the first frost comes before September 7 in 1 year out of 10, before September 18 in half of the years, before September 29 in 9 years out of 10. Typical frost-free season: 93 days.JFMAMJJASONDLast frost ~Jun 14First frost ~Sep 18
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 30September 7
50% (typical)June 14September 18
90% (likely)June 1September 29
Frost-free season (32°F, 50% chance)
93 days
Hard frost (28°F), last in spring, 50% chance after
June 1
Hard frost (28°F), first in fall, 50% chance before
September 26

The last 15 years (2006–2020 normals)

Typical last frost June 9 (5 days earlier than the 30-year normal), typical first fall frost September 22 (4 days later). Frost-free season 101 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 Chama: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 30, 20% June 25, 30% June 21, 40% June 18, 50% June 14, 60% June 11, 70% June 8, 80% June 5, 90% June 1. Observed last spring frost in recent years: 2021 May 30, 2022 May 31, 2023 June 23, 2024 June 2, 2025 May 27, 2026 June 21.Spring: last frostChance of a frost after this date10%50%90%Jun 1Jul 1Jun 30Jun 14Jun 12021: May 302022: May 312023: June 232024: June 22025: May 272026: June 21Fall at Chama: chance of a frost before this dateFall, chance of a frost before the date: 10% September 7, 20% September 11, 30% September 14, 40% September 16, 50% September 18, 60% September 21, 70% September 23, 80% September 25, 90% September 29. Observed first fall frost in recent years: 2022 September 17, 2023 September 21, 2024 September 3, 2025 September 14.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 7Sep 18Sep 292022: September 172023: September 212024: September 32025: September 14
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 30incomplete record
2022May 31September 17
2023June 23September 21
2024June 2September 3
2025May 27September 14
2026June 21season not over yet

What these dates mean

September 7 is the cautious fall date in Chama for finishing the harvest, because only a 10 % chance exists that a light frost has arrived earlier. In spring the cautious date for setting out tender crops is June 30, when the chance of a light frost later is also 10 %; planting on June 1 carries a 90 % chance of frost and is a gamble.

The 50 % dates—June 14 for spring and September 18 for fall—represent the median point at which a light frost is equally likely to occur before or after, giving gardeners a reference for the middle of the frost-risk window. Hard-frost median dates are June 1 and September 26; these are the points where a 28 °F frost is equally likely to have happened earlier or later.

A hard frost matters more because the lower temperature can damage plant tissue that survives a light frost.

How to read the probabilities

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

  • Spring: "10% after June 30" 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 7" 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 Chama, NMNumbered nearest stations: 1 — Dulce, NM — 23 mi; 2 — Monte Vista, CO — 51 mi; 3 — near Alamosa, CO — 53 mi; 4 — Wolf Canyon, NM — 68 mi; 5 — Los Alamos, NM — 74 mi.NMCO50 mi · 80 km1. Dulce, NM — 23 mi12. Monte Vista, CO — 51 mi23. near Alamosa, CO — 53 mi34. Wolf Canyon, NM — 68 mi45. Los Alamos, NM — 74 mi5
  1. Dulce, NM 23 mi (38 km)
  2. Monte Vista, CO 51 mi (81 km)
  3. near Alamosa, CO 53 mi (86 km)
  4. Wolf Canyon, NM 68 mi (109 km)
  5. Los Alamos, NM 74 mi (119 km)

Sources

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

Station coordinates: 36.9178, -106.5781.