U.S. Frost Dates by Weather Station

NOAA station USC00437607 · Vermont

Frost Dates for South Hero, VT

NOAA weather station South Hero (USC00437607), Vermont · elevation 110 ft (34 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 2850% chance of a frost after it
  • Typical first fall frostOctober 2050% chance of a frost before it
  • Frost-free season174 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at South Hero, VTSpring: a frost after April 19 in 9 years out of 10, after April 28 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 20 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 174 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 28First frost ~Oct 20Frost season at South Hero, VTSpring: a frost after April 19 in 9 years out of 10, after April 28 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 20 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 174 days.JFMAMJJASONDLast frost ~Apr 28First frost ~Oct 20
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 10October 4
50% (typical)April 28October 20
90% (likely)April 19November 2
Frost-free season (32°F, 50% chance)
174 days
Hard frost (28°F), last in spring, 50% chance after
April 18
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 27 (1 day earlier than the 30-year normal), typical first fall frost October 23 (3 days later). Frost-free season 178 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 South Hero: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 5, 30% May 3, 40% April 30, 50% April 28, 60% April 26, 70% April 24, 80% April 22, 90% April 19. Observed last spring frost in recent years: 2022 April 18.Spring: last frostChance of a frost after this date10%50%90%May 1May 10Apr 28Apr 192022: April 18Fall at South Hero: chance of a frost before this dateFall, chance of a frost before the date: 10% October 4, 20% October 9, 30% October 13, 40% October 16, 50% October 20, 60% October 23, 70% October 26, 80% October 29, 90% November 2. Observed first fall frost in recent years: 2022 November 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 4Oct 20Nov 22022: 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
2021no dataincomplete record
2022April 18November 10
2023incomplete recordincomplete record
2024incomplete recordincomplete record
2025incomplete recordno data
2026no dataseason not over yet

What these dates mean

October 4 is the cautious fall date in South Hero for finishing the harvest of tender crops, carrying only a 10 % chance that a light frost has arrived earlier.

The 50% date in spring is April 28, which carries a 50 % chance of a frost later than this date, and the 50% date in fall is October 20, which carries a 50 % chance of a frost earlier than this date. For a cautious plan, gardeners should wait until May 10 to set out tender crops in spring, since that date has only a 10 % chance of a later frost, and aim to complete harvest by October 4 in fall.

A hard frost at 28 °F is more damaging than a light frost at 32 °F, and its 50% dates are April 18 in spring and November 1 in fall.

How to read the probabilities

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

  • Spring: "10% after May 10" 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 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 South Hero, VTNumbered nearest stations: 1 — Burlington, VT — 13 mi; 2 — Peru, NY — 14 mi; 3 — Dannemora, NY — 21 mi; 4 — near Stowe, VT — 25 mi; 5 — Lake Placid, NY — 40 mi.NY25 mi · 40 km1. Burlington, VT — 13 mi12. Peru, NY — 14 mi23. Dannemora, NY — 21 mi34. near Stowe, VT — 25 mi45. Lake Placid, NY — 40 mi5
  1. Burlington, VT 13 mi (21 km)
  2. Peru, NY 14 mi (22 km)
  3. Dannemora, NY 21 mi (35 km)
  4. near Stowe, VT 25 mi (40 km)
  5. Lake Placid, NY 40 mi (65 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 44.6264, -73.3031.