U.S. Frost Dates by Weather Station

NOAA station USC00024453 · Arizona

Frost Dates for Jerome, AZ

NOAA weather station Jerome (USC00024453), Arizona · elevation 4950 ft (1509 m) · hardiness zone 9a*

  • Lower-risk planting dateafter April 19only 1 spring in 10 still has a frost later
  • Typical last frostMarch 2650% chance of a frost after it
  • Typical first fall frostNovember 2550% chance of a frost before it
  • Frost-free season242 daystypical year, 32°F
  • Hardiness zone9acalculated*

The year at a glance

Frost season at Jerome, AZSpring: a frost after February 28 in 9 years out of 10, after March 26 in half of the years, after April 19 in 1 year out of 10. Fall: the first frost comes before November 4 in 1 year out of 10, before November 25 in half of the years, before December 10 in 9 years out of 10. Typical frost-free season: 242 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 26First frost ~Nov 25Frost season at Jerome, AZSpring: a frost after February 28 in 9 years out of 10, after March 26 in half of the years, after April 19 in 1 year out of 10. Fall: the first frost comes before November 4 in 1 year out of 10, before November 25 in half of the years, before December 10 in 9 years out of 10. Typical frost-free season: 242 days.JFMAMJJASONDLast frost ~Mar 26First frost ~Nov 25
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)April 19November 4
50% (typical)March 26November 25
90% (likely)February 28December 10
Frost-free season (32°F, 50% chance)
242 days
Hard frost (28°F), last in spring, 50% chance after
March 1
Hard frost (28°F), first in fall, 50% chance before
December 6

The last 15 years (2006–2020 normals)

Typical last frost March 22 (4 days earlier than the 30-year normal), typical first fall frost November 25. Frost-free season 246 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 Jerome: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 19, 20% April 10, 30% April 5, 40% March 31, 50% March 26, 60% March 20, 70% March 15, 80% March 8, 90% February 28. Observed last spring frost in recent years: 2021 March 22, 2022 March 11, 2023 April 12, 2024 April 6, 2025 April 19, 2026 February 20.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1May 1Apr 19Mar 26Feb 282021: March 222022: March 112023: April 122024: April 62025: April 192026: February 20Fall at Jerome: chance of a frost before this dateFall, chance of a frost before the date: 10% November 4, 20% November 12, 30% November 17, 40% November 21, 50% November 25, 60% November 28, 70% December 1, 80% December 6, 90% December 10. Observed first fall frost in recent years: 2021 December 11, 2023 November 26, 2024 November 18.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Nov 4Nov 25Dec 102021: December 112023: November 262024: November 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
2021March 22December 11
2022March 11incomplete record
2023April 12November 26
2024April 6November 18
2025April 19incomplete record
2026February 20season not over yet

What these dates mean

November 4 is the cautious fall date in Jerome for finishing the harvest, meaning only a 10% chance that a light frost has arrived earlier. In spring the cautious date for setting out tender crops is April 19, which carries a 10% chance of a light frost later than that day. Planting before February 28 would be a gamble because it carries a 90% chance of a light frost later. These two dates bracket the period when tender crops are most likely to avoid a light frost.

The 50% light-frost dates are March 26 in spring and November 25 in fall; each marks an even-odds point, a 50% chance of a frost later than the spring date and a 50% chance of a frost earlier than the fall date. The hard-frost 50% dates are March 1 and December 6, showing when a temperature of 28 °F becomes equally likely. Hard frost matters more than light frost because the lower temperature can cause more severe damage to plants.

How to read the probabilities

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

  • Spring: "10% after April 19" 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 November 4" 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 Jerome, AZNumbered nearest stations: 1 — near Camp Verde, AZ — 18 mi; 2 — Prescott, AZ — 22 mi; 3 — Cordes, AZ — 31 mi; 4 — near Flagstaff, AZ — 37 mi; 5 — Walnut Creek, AZ — 41 mi.25 mi · 40 km1. near Camp Verde, AZ — 18 mi12. Prescott, AZ — 22 mi23. Cordes, AZ — 31 mi34. near Flagstaff, AZ — 37 mi45. Walnut Creek, AZ — 41 mi5
  1. near Camp Verde, AZ 18 mi (30 km)
  2. Prescott, AZ 22 mi (36 km)
  3. Cordes, AZ 31 mi (50 km)
  4. near Flagstaff, AZ 37 mi (60 km)
  5. Walnut Creek, AZ 41 mi (67 km)

Sources

* Hardiness zone 9a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 34.7522, -112.1114.