U.S. Frost Dates by Weather Station

NOAA station USC00315923 · North Carolina

Frost Dates for Mount Mitchell, NC

NOAA weather station Mount Mitchell (USC00315923), North Carolina · elevation 6240 ft (1902 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 31only 1 spring in 10 still has a frost later
  • Typical last frostMay 1650% chance of a frost after it
  • Typical first fall frostOctober 450% chance of a frost before it
  • Frost-free season140 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Mount Mitchell, NCSpring: a frost after May 3 in 9 years out of 10, after May 16 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 4 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 140 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 16First frost ~Oct 4Frost season at Mount Mitchell, NCSpring: a frost after May 3 in 9 years out of 10, after May 16 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 4 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 140 days.JFMAMJJASONDLast frost ~May 16First frost ~Oct 4
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.Today

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)May 31September 20
50% (typical)May 16October 4
90% (likely)May 3October 18
Frost-free season (32°F, 50% chance)
140 days
Hard frost (28°F), last in spring, 50% chance after
May 7
Hard frost (28°F), first in fall, 50% chance before
October 12

The last 15 years (2006–2020 normals)

Typical last frost May 15 (1 day earlier than the 30-year normal), typical first fall frost October 8 (4 days later). Frost-free season 144 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 Mount Mitchell: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 31, 20% May 27, 30% May 23, 40% May 19, 50% May 16, 60% May 13, 70% May 11, 80% May 7, 90% May 3. Observed last spring frost in recent years: 2021 May 14, 2022 April 27, 2023 May 5, 2024 May 12, 2026 May 15.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 31May 16May 32021: May 142022: April 272023: May 52024: May 122026: May 15Fall at Mount Mitchell: chance of a frost before this dateFall, chance of a frost before the date: 10% September 20, 20% September 26, 30% September 29, 40% October 2, 50% October 4, 60% October 7, 70% October 10, 80% October 13, 90% October 18. Observed first fall frost in recent years: 2021 September 24, 2022 September 28, 2023 October 8, 2025 October 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 20Oct 4Oct 182021: September 242022: September 282023: October 82025: October 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
2021May 14September 24
2022April 27September 28
2023May 5October 8
2024May 12incomplete record
2025incomplete recordOctober 10
2026May 15season not over yet

What these dates mean

September 20 is the cautious fall date for finishing the harvest of tender crops at Mount Mitchell, carrying only a 10 % chance that a light frost has arrived earlier.

The 50 % dates mark the point where a light frost is equally likely to occur later (spring) or earlier (fall). At this station the 50 % date for spring light frost is May 16, and the 50 % date for fall light frost is October 4. The 50 % hard-frost dates, when temperatures reach 28 °F, are May 7 in spring and October 12 in fall. These median dates reflect a 50 % chance of frost relative to the date.

A cautious planting plan therefore uses May 31 as the spring date to set out tender crops, and September 20 as the fall date to end their harvest. Because a hard frost at 28 °F can damage plant tissue more severely than a light frost at 32 °F, it is the more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 31" 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 September 20" 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 Mount Mitchell, NCNumbered nearest stations: 1 — Asheville, NC — 20 mi; 2 — Marshall, NC — 22 mi; 3 — Bent Creek, NC — 25 mi; 4 — Asheville (Airport), NC — 27 mi; 5 — Erwin, TN — 28 mi.TNSCVA25 mi · 40 km1. Asheville, NC — 20 mi12. Marshall, NC — 22 mi23. Bent Creek, NC — 25 mi34. Asheville (Airport), NC — 27 mi45. Erwin, TN — 28 mi5
  1. Asheville, NC 20 mi (32 km)
  2. Marshall, NC 22 mi (36 km)
  3. Bent Creek, NC 25 mi (41 km)
  4. Asheville (Airport), NC 27 mi (44 km)
  5. Erwin, TN 28 mi (45 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 35.7586, -82.2711.