U.S. Frost Dates by Weather Station

NOAA station USC00309000 · New York

Frost Dates for Watertown, NY

NOAA weather station Watertown (USC00309000), New York · elevation 497 ft (152 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 17only 1 spring in 10 still has a frost later
  • Typical last frostMay 250% chance of a frost after it
  • Typical first fall frostOctober 1350% chance of a frost before it
  • Frost-free season163 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Watertown, NYSpring: a frost after April 20 in 9 years out of 10, after May 2 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 13 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 163 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 2First frost ~Oct 13Frost season at Watertown, NYSpring: a frost after April 20 in 9 years out of 10, after May 2 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 13 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 163 days.JFMAMJJASONDLast frost ~May 2First frost ~Oct 13
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 17October 1
50% (typical)May 2October 13
90% (likely)April 20October 28
Frost-free season (32°F, 50% chance)
163 days
Hard frost (28°F), last in spring, 50% chance after
April 22
Hard frost (28°F), first in fall, 50% chance before
October 25

The last 15 years (2006–2020 normals)

Typical last frost May 1 (1 day earlier than the 30-year normal), typical first fall frost October 19 (6 days later). Frost-free season 169 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 Watertown: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 17, 20% May 12, 30% May 8, 40% May 5, 50% May 2, 60% April 30, 70% April 27, 80% April 24, 90% April 20. Observed last spring frost in recent years: 2021 May 2, 2022 May 1, 2023 April 27, 2024 April 27, 2025 April 23, 2026 May 12.Spring: last frostChance of a frost after this date10%50%90%May 1May 17May 2Apr 202021: May 22022: May 12023: April 272024: April 272025: April 232026: May 12Fall at Watertown: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 3, 30% October 6, 40% October 9, 50% October 13, 60% October 16, 70% October 19, 80% October 23, 90% October 28. Observed first fall frost in recent years: 2021 November 4, 2022 October 3, 2023 October 31, 2024 October 15, 2025 October 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 13Oct 282021: November 42022: October 32023: October 312024: 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 2November 4
2022May 1October 3
2023April 27October 31
2024April 27October 15
2025April 23October 9
2026May 12season not over yet

What these dates mean

The 163 days between the 32°F 50% dates, May 2 and October 13, frame the period when temperatures are more likely to stay above a light frost. For a gardener this means there is a 50% chance of a frost later than May 2 in spring and a 50% chance of a frost earlier than October 13 in fall; outside this window the risk rises sharply.

In Watertown the cautious spring date for setting out tender crops is May 17, when only a 10% chance of a light frost remains later, while the cautious fall date to finish harvesting tender crops is October 1, with only a 10% chance of a light frost earlier. Hard frosts at 28°F, noted by April 22 in spring and October 25 in fall, pose a greater threat to plant tissue than the milder 32°F 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 17" 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 1" 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 Watertown, NYNumbered nearest stations: 1 — Watertown (Airport), NY — 7 mi; 2 — Lowville, NY — 23 mi; 3 — Gouverneur, NY — 32 mi; 4 — Boonville, NY — 45 mi; 5 — Oswego, NY — 49 mi.25 mi · 40 km1. Watertown (Airport), NY — 7 mi12. Lowville, NY — 23 mi23. Gouverneur, NY — 32 mi34. Boonville, NY — 45 mi45. Oswego, NY — 49 mi5
  1. Watertown (Airport), NY 7 mi (12 km)
  2. Lowville, NY 23 mi (37 km)
  3. Gouverneur, NY 32 mi (51 km)
  4. Boonville, NY 45 mi (73 km)
  5. Oswego, NY 49 mi (79 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: 43.9761, -75.8753.