U.S. Frost Dates by Weather Station

NOAA station USC00406619 · Tennessee

Frost Dates for Norris, TN

NOAA weather station Norris (USC00406619), Tennessee · elevation 1110 ft (338 m) · hardiness zone 7b*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2250% chance of a frost after it
  • Typical first fall frostOctober 2550% chance of a frost before it
  • Frost-free season184 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season at Norris, TNSpring: a frost after April 6 in 9 years out of 10, after April 22 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 25 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 184 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 22First frost ~Oct 25Frost season at Norris, TNSpring: a frost after April 6 in 9 years out of 10, after April 22 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 11 in 1 year out of 10, before October 25 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 184 days.JFMAMJJASONDLast frost ~Apr 22First frost ~Oct 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 9October 11
50% (typical)April 22October 25
90% (likely)April 6November 6
Frost-free season (32°F, 50% chance)
184 days
Hard frost (28°F), last in spring, 50% chance after
April 7
Hard frost (28°F), first in fall, 50% chance before
November 3

The last 15 years (2006–2020 normals)

Typical last frost April 22 (same as the 30-year normal), typical first fall frost October 26 (1 day later). Frost-free season 184 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 Norris: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 2, 30% April 30, 40% April 26, 50% April 22, 60% April 18, 70% April 15, 80% April 11, 90% April 6. Observed last spring frost in recent years: 2021 April 24, 2022 April 12, 2023 April 28, 2024 April 23, 2025 April 13.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 22Apr 62021: April 242022: April 122023: April 282024: April 232025: April 13Fall at Norris: chance of a frost before this dateFall, chance of a frost before the date: 10% October 11, 20% October 15, 30% October 19, 40% October 22, 50% October 25, 60% October 27, 70% October 30, 80% November 1, 90% November 6. Observed first fall frost in recent years: 2021 November 5, 2022 October 18, 2023 November 1, 2024 October 17, 2025 October 24.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 11Oct 25Nov 62021: November 52022: October 182023: November 12024: October 172025: October 24
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 24November 5
2022April 12October 18
2023April 28November 1
2024April 23October 17
2025April 13October 24
2026incomplete recordseason not over yet

What these dates mean

May 9 is the cautious spring date, with only a 10 % chance of a light frost later, so a gardener can plan to set out tender crops on that day with confidence.

The 50% date of April 22 marks the point at which a light frost is equally likely to occur later or not, while October 25 serves the same function for fall. The 28 °F median dates are April 7 and November 3; a hard frost can injure plants that survive a light frost, so its timing is more critical. October 11 is the cautious fall date, carrying only a 10 % chance that a light frost has already arrived, and it guides the latest time to finish harvesting tender crops.

Because a hard frost reaches 28 °F, it can kill tissue that survives a 32 °F light frost, making those dates especially relevant for protecting sensitive plants.

How to read the probabilities

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

  • Spring: "10% after May 9" 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 11" 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 Norris, TNNumbered nearest stations: 1 — near Oak Ridge, TN — 18 mi; 2 — near Knoxville, TN — 23 mi; 3 — Knoxville (McGhee Tyson Airport), TN — 28 mi; 4 — Lenoir City, TN — 31 mi; 5 — Sevierville, TN — 32 mi.TNNCKYVA25 mi · 40 km1. near Oak Ridge, TN — 18 mi12. near Knoxville, TN — 23 mi23. Knoxville (McGhee Tyson Airport), TN — 28 mi34. Lenoir City, TN — 31 mi45. Sevierville, TN — 32 mi5
  1. near Oak Ridge, TN 18 mi (29 km)
  2. near Knoxville, TN 23 mi (36 km)
  3. Knoxville (McGhee Tyson Airport), TN 28 mi (44 km)
  4. Lenoir City, TN 31 mi (51 km)
  5. Sevierville, TN 32 mi (52 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: 36.2131, -84.0603.