U.S. Frost Dates by Weather Station

NOAA station USC00027716 · Arizona

Frost Dates for Seligman, AZ

NOAA weather station Seligman (USC00027716), Arizona · elevation 5250 ft (1600 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 29only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostOctober 1550% chance of a frost before it
  • Frost-free season154 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Seligman, AZSpring: a frost after April 26 in 9 years out of 10, after May 10 in half of the years, after May 29 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 15 in half of the years, before October 30 in 9 years out of 10. Typical frost-free season: 154 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Oct 15Frost season at Seligman, AZSpring: a frost after April 26 in 9 years out of 10, after May 10 in half of the years, after May 29 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 15 in half of the years, before October 30 in 9 years out of 10. Typical frost-free season: 154 days.JFMAMJJASONDLast frost ~May 10First frost ~Oct 15
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)May 29October 1
50% (typical)May 10October 15
90% (likely)April 26October 30
Frost-free season (32°F, 50% chance)
154 days
Hard frost (28°F), last in spring, 50% chance after
April 24
Hard frost (28°F), first in fall, 50% chance before
October 26

The last 15 years (2006–2020 normals)

Typical last frost May 9 (1 day earlier than the 30-year normal), typical first fall frost October 12 (3 days earlier). Frost-free season 155 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 Seligman: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 29, 20% May 22, 30% May 17, 40% May 14, 50% May 10, 60% May 6, 70% May 3, 80% April 30, 90% April 26. Observed last spring frost in recent years: 2021 May 23, 2022 May 13, 2023 May 6, 2024 May 7.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 29May 10Apr 262021: May 232022: May 132023: May 62024: May 7Fall at Seligman: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 5, 30% October 8, 40% October 11, 50% October 15, 60% October 18, 70% October 21, 80% October 24, 90% October 30.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 15Oct 30
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 23incomplete record
2022May 13incomplete record
2023May 6incomplete record
2024May 7incomplete record
2025incomplete recordincomplete record
2026incomplete recordseason not over yet

What these dates mean

October 1 is the cautious date to finish harvesting tender crops in Seligman, because there is only a 10 % chance that a light frost has arrived earlier.

The 50 % light-frost dates – May 10 in spring and October 15 in fall – indicate the median point of frost risk; at each of those dates a light frost has a 50 % chance of having occurred. For a cautious plan, tender crops should be set out after the spring cautious date of May 29 (10 % chance of a later frost) and harvested before the fall cautious date of October 1. A hard frost at 28 °F, noted on April 24 in spring and October 26 in fall, matters more than a light frost because the lower temperature can cause greater plant damage.

How to read the probabilities

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

  • Spring: "10% after May 29" 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 Seligman, AZNumbered nearest stations: 1 — Walnut Creek, AZ — 28 mi; 2 — Bagdad, AZ — 53 mi; 3 — Prescott, AZ — 58 mi; 4 — Jerome, AZ — 59 mi; 5 — near Grand Canyon Village, AZ — 69 mi.AZ50 mi · 80 km1. Walnut Creek, AZ — 28 mi12. Bagdad, AZ — 53 mi23. Prescott, AZ — 58 mi34. Jerome, AZ — 59 mi45. near Grand Canyon Village, AZ — 69 mi5
  1. Walnut Creek, AZ 28 mi (45 km)
  2. Bagdad, AZ 53 mi (86 km)
  3. Prescott, AZ 58 mi (94 km)
  4. Jerome, AZ 59 mi (95 km)
  5. near Grand Canyon Village, AZ 69 mi (112 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: 35.3322, -112.8797.