U.S. Frost Dates by Weather Station

NOAA station USC00300785 · New York

Frost Dates for Boonville, NY

NOAA weather station Boonville 4 SSW (USC00300785), New York · elevation 1550 ft (472 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 28only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostOctober 450% chance of a frost before it
  • Frost-free season145 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Boonville, NYSpring: a frost after April 28 in 9 years out of 10, after May 10 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 22 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: 145 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Oct 4Frost season at Boonville, NYSpring: a frost after April 28 in 9 years out of 10, after May 10 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 22 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: 145 days.JFMAMJJASONDLast frost ~May 10First 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.

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 28September 22
50% (typical)May 10October 4
90% (likely)April 28October 18
Frost-free season (32°F, 50% chance)
145 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 15

The last 15 years (2006–2020 normals)

Typical last frost May 9 (1 day earlier than the 30-year normal), typical first fall frost October 9 (5 days later). Frost-free season 151 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 Boonville: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 28, 20% May 22, 30% May 18, 40% May 14, 50% May 10, 60% May 7, 70% May 4, 80% May 1, 90% April 28. Observed last spring frost in recent years: 2021 May 11, 2022 May 9, 2023 May 25, 2024 April 27, 2025 April 27, 2026 May 13.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 28May 10Apr 282021: May 112022: May 92023: May 252024: April 272025: April 272026: May 13Fall at Boonville: chance of a frost before this dateFall, chance of a frost before the date: 10% September 22, 20% September 27, 30% September 29, 40% October 1, 50% October 4, 60% October 6, 70% October 9, 80% October 13, 90% October 18. Observed first fall frost in recent years: 2021 October 23, 2022 October 3, 2023 October 13, 2024 October 15, 2025 October 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 22Oct 4Oct 182021: October 232022: October 32023: October 132024: October 152025: October 9
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 11October 23
2022May 9October 3
2023May 25October 13
2024April 27October 15
2025April 27October 9
2026May 13season not over yet

What these dates mean

Setting out tender crops on April 28 in Boonville is a gamble, because a 90 % chance of a light frost follows that date.

The cautious spring date is May 28, when only a 10 % chance of a light frost remains; the 50 % light-frost date is May 10, meaning a 50 % chance of a frost later than that day. In fall the cautious date to finish tender crops is September 22, with a 10 % chance of a frost earlier than then, and the 50 % light-frost date is October 4, meaning a 50 % chance of a frost earlier than that day.

The 50 % hard-frost dates are April 30 in spring and October 15 in fall, each an even-odds point for a 28 °F frost, which can damage plants more severely than a 32 °F light frost.

How to read the probabilities

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

  • Spring: "10% after May 28" 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 22" 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 Boonville, NYNumbered nearest stations: 1 — Lowville, NY — 25 mi; 2 — near Syracuse, NY — 43 mi; 3 — Watertown, NY — 45 mi; 4 — Watertown (Airport), NY — 50 mi; 5 — Sherburne, NY — 53 mi.NY25 mi · 40 km1. Lowville, NY — 25 mi12. near Syracuse, NY — 43 mi23. Watertown, NY — 45 mi34. Watertown (Airport), NY — 50 mi45. Sherburne, NY — 53 mi5
  1. Lowville, NY 25 mi (41 km)
  2. near Syracuse, NY 43 mi (70 km)
  3. Watertown, NY 45 mi (73 km)
  4. Watertown (Airport), NY 50 mi (81 km)
  5. Sherburne, NY 53 mi (85 km)

Sources

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

Station coordinates: 43.4361, -75.3697.