U.S. Frost Dates by Weather Station

NOAA station USC00292785 · New Mexico

Frost Dates for El Morro National Monument, NM

NOAA weather station El Morro National Monument (USC00292785), New Mexico · elevation 7223 ft (2202 m) · hardiness zone 5b*

  • Lower-risk planting dateafter June 15only 1 spring in 10 still has a frost later
  • Typical last frostJune 350% chance of a frost after it
  • Typical first fall frostSeptember 2750% chance of a frost before it
  • Frost-free season114 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at El Morro National Monument, NMSpring: a frost after May 20 in 9 years out of 10, after June 3 in half of the years, after June 15 in 1 year out of 10. Fall: the first frost comes before September 14 in 1 year out of 10, before September 27 in half of the years, before October 7 in 9 years out of 10. Typical frost-free season: 114 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Jun 3First frost ~Sep 27Frost season at El Morro National Monument, NMSpring: a frost after May 20 in 9 years out of 10, after June 3 in half of the years, after June 15 in 1 year out of 10. Fall: the first frost comes before September 14 in 1 year out of 10, before September 27 in half of the years, before October 7 in 9 years out of 10. Typical frost-free season: 114 days.JFMAMJJASONDLast frost ~Jun 3First frost ~Sep 27
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 15September 14
50% (typical)June 3September 27
90% (likely)May 20October 7
Frost-free season (32°F, 50% chance)
114 days
Hard frost (28°F), last in spring, 50% chance after
May 20
Hard frost (28°F), first in fall, 50% chance before
October 4

The last 15 years (2006–2020 normals)

Typical last frost June 2 (1 day earlier than the 30-year normal), typical first fall frost September 29 (2 days later). Frost-free season 117 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 El Morro National Monument: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 15, 20% June 11, 30% June 8, 40% June 5, 50% June 3, 60% June 1, 70% May 29, 80% May 25, 90% May 20. Observed last spring frost in recent years: 2021 May 31, 2022 June 16, 2025 May 27, 2026 May 21.Spring: last frostChance of a frost after this date10%50%90%Jun 1Jun 15Jun 3May 202021: May 312022: June 162025: May 272026: May 21Fall at El Morro National Monument: chance of a frost before this dateFall, chance of a frost before the date: 10% September 14, 20% September 19, 30% September 22, 40% September 24, 50% September 27, 60% September 29, 70% October 1, 80% October 3, 90% October 7. Observed first fall frost in recent years: 2021 September 21, 2022 October 12, 2024 October 19.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 14Sep 27Oct 72021: September 212022: October 122024: October 19
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 31September 21
2022June 16October 12
2023incomplete recordincomplete record
2024incomplete recordOctober 19
2025May 27incomplete record
2026May 21season not over yet

What these dates mean

Setting out tender crops on the early spring date May 20 is a gamble, because there is a 90% chance that a light frost will occur later in the season at El Morro National Monument.

The 50% dates—June 3 for spring and September 27 for fall—mark the point where the odds of a 32°F frost are even. Gardeners who prefer a lower risk choose the cautious dates: June 15, which carries only a 10% chance of a later frost in spring, and September 14, which carries only a 10% chance of an earlier frost in fall.

A hard frost at 28°F, represented by the median dates May 20 and October 4, can injure or kill plants that would survive the milder 32°F 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 15" 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 14" 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 El Morro National Monument, NMNumbered nearest stations: 1 — Zuni, NM — 28 mi; 2 — Saint Johns, AZ — 70 mi; 3 — Augustine, NM — 78 mi; 4 — Springerville, AZ — 82 mi; 5 — Torreon Navajo Mission, NM — 84 mi.NMAZ50 mi · 80 km1. Zuni, NM — 28 mi12. Saint Johns, AZ — 70 mi23. Augustine, NM — 78 mi34. Springerville, AZ — 82 mi45. Torreon Navajo Mission, NM — 84 mi5
  1. Zuni, NM 28 mi (45 km)
  2. Saint Johns, AZ 70 mi (112 km)
  3. Augustine, NM 78 mi (126 km)
  4. Springerville, AZ 82 mi (132 km)
  5. Torreon Navajo Mission, NM 84 mi (136 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: 35.0381, -108.3492.