U.S. Frost Dates by Weather Station

NOAA station USC00295084 · New Mexico

Frost Dates for Los Alamos, NM

NOAA weather station Los Alamos (USC00295084), New Mexico · elevation 7424 ft (2263 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 17only 1 spring in 10 still has a frost later
  • Typical last frostMay 250% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season162 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Los Alamos, NMSpring: a frost after April 19 in 9 years out of 10, after May 2 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 12 in half of the years, before October 25 in 9 years out of 10. Typical frost-free season: 162 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 2First frost ~Oct 12Frost season at Los Alamos, NMSpring: a frost after April 19 in 9 years out of 10, after May 2 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 12 in half of the years, before October 25 in 9 years out of 10. Typical frost-free season: 162 days.JFMAMJJASONDLast frost ~May 2First frost ~Oct 12
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 27 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 17October 1
50% (typical)May 2October 12
90% (likely)April 19October 25
Frost-free season (32°F, 50% chance)
162 days
Hard frost (28°F), last in spring, 50% chance after
April 20
Hard frost (28°F), first in fall, 50% chance before
October 23

The last 15 years (2006–2020 normals)

Typical last frost May 6 (4 days later than the 30-year normal), typical first fall frost October 15 (3 days later). Frost-free season 162 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 Los Alamos: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 17, 20% May 13, 30% May 9, 40% May 4, 50% May 2, 60% April 30, 70% April 27, 80% April 23, 90% April 19. Observed last spring frost in recent years: 2021 April 24, 2022 April 24, 2023 April 28, 2024 April 28, 2025 May 20, 2026 May 2.Spring: last frostChance of a frost after this date10%50%90%May 1May 17May 2Apr 192021: April 242022: April 242023: April 282024: April 282025: May 202026: May 2Fall at Los Alamos: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 3, 30% October 6, 40% October 9, 50% October 12, 60% October 15, 70% October 18, 80% October 21, 90% October 25. Observed first fall frost in recent years: 2022 October 24, 2023 October 13, 2024 October 30, 2025 October 18.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 12Oct 252022: October 242023: October 132024: October 302025: October 18
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
2021April 24incomplete record
2022April 24October 24
2023April 28October 13
2024April 28October 30
2025May 20October 18
2026May 2season not over yet

What these dates mean

Planting tender crops on the early spring date of April 19 in Los Alamos is a gamble, because there is a 90 % chance of a light frost occurring later.

For a gardener, the 50 % dates—May 2 in spring and October 12 in fall—represent the point at which a light frost has a 50 % chance of occurring later in spring or earlier in fall. The cautious approach uses the later spring date of May 17, which carries only a 10 % chance of a subsequent frost, and the early fall date of October 1, which has only a 10 % chance that a frost has already arrived. A hard frost at 28 °F, reflected by the median dates of April 20 and October 23, can damage plants that would survive a light frost at 32 °F, making it a more serious threat.

How to read the probabilities

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

  • Spring: "10% after May 17" 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 October 1" 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 Los Alamos, NMNumbered nearest stations: 1 — Wolf Canyon, NM — 25 mi; 2 — Santa Fe, NM — 26 mi; 3 — Torreon Navajo Mission, NM — 48 mi; 4 — Gascon, NM — 49 mi; 5 — Albuquerque, NM — 59 mi.NM25 mi · 40 km1. Wolf Canyon, NM — 25 mi12. Santa Fe, NM — 26 mi23. Torreon Navajo Mission, NM — 48 mi34. Gascon, NM — 49 mi45. Albuquerque, NM — 59 mi5
  1. Wolf Canyon, NM 25 mi (39 km)
  2. Santa Fe, NM 26 mi (41 km)
  3. Torreon Navajo Mission, NM 48 mi (78 km)
  4. Gascon, NM 49 mi (79 km)
  5. Albuquerque, NM 59 mi (95 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 35.8644, -106.3214.