U.S. Frost Dates by Weather Station

NOAA station USC00013645 · Alabama

Frost Dates for Hamilton, AL

NOAA weather station Hamilton 3 S (USC00013645), Alabama · elevation 435 ft (133 m) · hardiness zone 7b*

  • Lower-risk planting dateafter April 27only 1 spring in 10 still has a frost later
  • Typical last frostApril 1150% chance of a frost after it
  • Typical first fall frostOctober 2750% chance of a frost before it
  • Frost-free season198 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Hamilton, ALSpring: a frost after March 26 in 9 years out of 10, after April 11 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 15 in 1 year out of 10, before October 27 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 198 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 11First frost ~Oct 27Frost season at Hamilton, ALSpring: a frost after March 26 in 9 years out of 10, after April 11 in half of the years, after April 27 in 1 year out of 10. Fall: the first frost comes before October 15 in 1 year out of 10, before October 27 in half of the years, before November 10 in 9 years out of 10. Typical frost-free season: 198 days.JFMAMJJASONDLast frost ~Apr 11First frost ~Oct 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)April 27October 15
50% (typical)April 11October 27
90% (likely)March 26November 10
Frost-free season (32°F, 50% chance)
198 days
Hard frost (28°F), last in spring, 50% chance after
March 31
Hard frost (28°F), first in fall, 50% chance before
November 4

The last 15 years (2006–2020 normals)

Typical last frost April 12 (1 day later than the 30-year normal), typical first fall frost October 30 (3 days later). Frost-free season 199 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 Hamilton: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 27, 20% April 22, 30% April 18, 40% April 14, 50% April 11, 60% April 8, 70% April 5, 80% March 31, 90% March 26. Observed last spring frost in recent years: 2023 March 22, 2024 March 21, 2026 March 18.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 27Apr 11Mar 262023: March 222024: March 212026: March 18Fall at Hamilton: chance of a frost before this dateFall, chance of a frost before the date: 10% October 15, 20% October 19, 30% October 22, 40% October 25, 50% October 27, 60% October 30, 70% November 1, 80% November 3, 90% November 10. Observed first fall frost in recent years: 2022 October 19, 2023 November 1, 2024 November 21.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 15Oct 27Nov 102022: October 192023: November 12024: November 21
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
2021no dataincomplete record
2022incomplete recordOctober 19
2023March 22November 1
2024March 21November 21
2025incomplete recordincomplete record
2026March 18season not over yet

What these dates mean

The 198 days between the 50% dates in Hamilton—April 11 and October 27—frame the stretch during which a light frost has an even chance of occurring either earlier or later. For gardeners this interval marks the central window of growing-season risk based on the historic record.

The cautious spring date for setting out tender crops is April 27, which carries only a 10 % chance that frost will arrive later. Planting before March 26 would be a gamble because a frost later than that date occurs 90 % of the time. In fall the cautious date to finish harvesting tender crops is October 15, with only a 10 % chance that frost has already arrived; waiting until November 10 would be a gamble, as a frost earlier than that date is 90 % likely.

A hard frost at 28 °F can injure plants that survive a light frost at 32 °F, so it represents a more severe risk.

How to read the probabilities

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

  • Spring: "10% after April 27" 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 15" 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 Hamilton, ALNumbered nearest stations: 1 — Winfield, AL — 15 mi; 2 — Haleyville, AL — 22 mi; 3 — Verona, MS — 42 mi; 4 — Tupelo, MS — 46 mi; 5 — Muscle Shoals, AL — 50 mi.TN25 mi · 40 km1. Winfield, AL — 15 mi12. Haleyville, AL — 22 mi23. Verona, MS — 42 mi34. Tupelo, MS — 46 mi45. Muscle Shoals, AL — 50 mi5
  1. Winfield, AL 15 mi (25 km)
  2. Haleyville, AL 22 mi (36 km)
  3. Verona, MS 42 mi (68 km)
  4. Tupelo, MS 46 mi (74 km)
  5. Muscle Shoals, AL 50 mi (80 km)

Sources

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

Station coordinates: 34.0967, -87.9914.