U.S. Frost Dates by Weather Station

NOAA station USC00402360 · Tennessee

Frost Dates for Dayton, TN

NOAA weather station Dayton 2 SE (USC00402360), Tennessee · elevation 822 ft (251 m) · hardiness zone 7b*

  • Lower-risk planting dateafter April 22only 1 spring in 10 still has a frost later
  • Typical last frostApril 450% chance of a frost after it
  • Typical first fall frostOctober 3150% chance of a frost before it
  • Frost-free season208 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Dayton, TNSpring: a frost after March 18 in 9 years out of 10, after April 4 in half of the years, after April 22 in 1 year out of 10. Fall: the first frost comes before October 19 in 1 year out of 10, before October 31 in half of the years, before November 12 in 9 years out of 10. Typical frost-free season: 208 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 4First frost ~Oct 31Frost season at Dayton, TNSpring: a frost after March 18 in 9 years out of 10, after April 4 in half of the years, after April 22 in 1 year out of 10. Fall: the first frost comes before October 19 in 1 year out of 10, before October 31 in half of the years, before November 12 in 9 years out of 10. Typical frost-free season: 208 days.JFMAMJJASONDLast frost ~Apr 4First frost ~Oct 31
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 22October 19
50% (typical)April 4October 31
90% (likely)March 18November 12
Frost-free season (32°F, 50% chance)
208 days
Hard frost (28°F), last in spring, 50% chance after
March 26
Hard frost (28°F), first in fall, 50% chance before
November 10

The last 15 years (2006–2020 normals)

Typical last frost April 4 (same as the 30-year normal), typical first fall frost November 1 (1 day later). Frost-free season 212 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 Dayton: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 22, 20% April 16, 30% April 11, 40% April 7, 50% April 4, 60% April 1, 70% March 30, 80% March 25, 90% March 18. Observed last spring frost in recent years: 2021 April 23, 2022 April 11, 2023 March 22, 2024 March 20, 2025 April 10, 2026 March 29.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 22Apr 4Mar 182021: April 232022: April 112023: March 222024: March 202025: April 102026: March 29Fall at Dayton: chance of a frost before this dateFall, chance of a frost before the date: 10% October 19, 20% October 22, 30% October 26, 40% October 28, 50% October 31, 60% November 1, 70% November 4, 80% November 8, 90% November 12. Observed first fall frost in recent years: 2021 November 6, 2022 October 18, 2023 November 1, 2024 November 24, 2025 November 10.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 19Oct 31Nov 122021: November 62022: October 182023: November 12024: November 242025: November 10
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 23November 6
2022April 11October 18
2023March 22November 1
2024March 20November 24
2025April 10November 10
2026March 29season not over yet

What these dates mean

April 22 is the cautious spring date for Dayton; with only a 10 % chance of a light frost after that day, a gardener can plan to set out tender crops with minimal risk. The 50% date in spring is April 4, the point at which there is an even chance of a light frost occurring later, and the hard-frost 50% date is March 26, marking an equal likelihood of a 28 °F freeze.

In fall, October 19 serves as the cautious date to finish harvesting tender crops, because only a 10 % chance exists that a light frost has arrived earlier. The 50% fall date for light frost is October 31, where the odds of a frost before that day are even, and the hard-frost 50% date is November 10.

A hard frost at 28 °F matters more than a light frost at 32 °F because it can damage plant tissue that would survive the milder temperature.

How to read the probabilities

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

  • Spring: "10% after April 22" 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 19" 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 Dayton, TNNumbered nearest stations: 1 — Pikeville, TN — 14 mi; 2 — Cleveland, TN — 21 mi; 3 — Athens, TN — 23 mi; 4 — near Chattanooga, TN — 33 mi; 5 — Crossville, TN — 33 mi.GANC25 mi · 40 km1. Pikeville, TN — 14 mi12. Cleveland, TN — 21 mi23. Athens, TN — 23 mi34. near Chattanooga, TN — 33 mi45. Crossville, TN — 33 mi5
  1. Pikeville, TN 14 mi (23 km)
  2. Cleveland, TN 21 mi (34 km)
  3. Athens, TN 23 mi (38 km)
  4. near Chattanooga, TN 33 mi (52 km)
  5. Crossville, TN 33 mi (54 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: 35.4722, -84.9958.