U.S. Frost Dates by Weather Station

NOAA station USC00068138 · Connecticut

Frost Dates for Storrs, CT

NOAA weather station Storrs (USC00068138), Connecticut · elevation 665 ft (203 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 3only 1 spring in 10 still has a frost later
  • Typical last frostApril 1950% chance of a frost after it
  • Typical first fall frostOctober 2250% chance of a frost before it
  • Frost-free season186 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Storrs, CTSpring: a frost after April 7 in 9 years out of 10, after April 19 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 22 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 186 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 19First frost ~Oct 22Frost season at Storrs, CTSpring: a frost after April 7 in 9 years out of 10, after April 19 in half of the years, after May 3 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 22 in half of the years, before November 6 in 9 years out of 10. Typical frost-free season: 186 days.JFMAMJJASONDLast frost ~Apr 19First frost ~Oct 22
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 3October 6
50% (typical)April 19October 22
90% (likely)April 7November 6
Frost-free season (32°F, 50% chance)
186 days
Hard frost (28°F), last in spring, 50% chance after
April 6
Hard frost (28°F), first in fall, 50% chance before
November 4

The last 15 years (2006–2020 normals)

Typical last frost April 18 (1 day earlier than the 30-year normal), typical first fall frost October 26 (4 days later). Frost-free season 191 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 Storrs: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 3, 20% April 29, 30% April 25, 40% April 22, 50% April 19, 60% April 17, 70% April 14, 80% April 11, 90% April 7. Observed last spring frost in recent years: 2021 April 23, 2022 April 18, 2023 May 18, 2024 April 26, 2025 April 13, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 3Apr 19Apr 72021: April 232022: April 182023: May 182024: April 262025: April 132026: April 21Fall at Storrs: chance of a frost before this dateFall, chance of a frost before the date: 10% October 6, 20% October 11, 30% October 15, 40% October 19, 50% October 22, 60% October 25, 70% October 29, 80% November 1, 90% November 6. Observed first fall frost in recent years: 2021 November 4, 2022 October 29, 2023 November 2, 2024 November 3, 2025 November 3.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 6Oct 22Nov 62021: November 42022: October 292023: November 22024: November 32025: November 3
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 23November 4
2022April 18October 29
2023May 18November 2
2024April 26November 3
2025April 13November 3
2026April 21season not over yet

What these dates mean

May 3, the cautious spring date, gives a gardener a low-risk window to set out tender crops, as only a 10% chance of a light frost remains after that day.

The 50% light-frost dates are April 19 in spring and October 22 in fall; each marks an even, 50% chance of frost later (spring) or earlier (fall). The cautious fall date, October 6, provides a low-risk point to finish harvesting tender crops, with only a 10% chance that a light frost has already arrived. The climate normals span 26 years, and the interval between the two 32 °F 50% dates is 186 days, giving a sense of the season’s balanced frost probability window.

A hard frost at 28 °F, with median dates of April 6 and November 4, is more damaging because it can kill plants that survive 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 3" 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 6" 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 Storrs, CTNumbered nearest stations: 1 — near Norwich, CT — 20 mi; 2 — Hartford (Brainard Field), CT — 22 mi; 3 — near Fiskdale, MA — 22 mi; 4 — Hartford (Bradley Airport), CT — 25 mi; 5 — North Foster, RI — 26 mi.RINY25 mi · 40 km1. near Norwich, CT — 20 mi12. Hartford (Brainard Field), CT — 22 mi23. near Fiskdale, MA — 22 mi34. Hartford (Bradley Airport), CT — 25 mi45. North Foster, RI — 26 mi5
  1. near Norwich, CT 20 mi (33 km)
  2. Hartford (Brainard Field), CT 22 mi (36 km)
  3. near Fiskdale, MA 22 mi (36 km)
  4. Hartford (Bradley Airport), CT 25 mi (41 km)
  5. North Foster, RI 26 mi (42 km)

Sources

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

Station coordinates: 41.795, -72.2286.