U.S. Frost Dates by Weather Station

NOAA station USC00065910 · Connecticut

Frost Dates near Norwich, CT

NOAA weather station Norwich Public Utility Plant (USC00065910), Connecticut · elevation 20 ft (6 m) · hardiness zone 6b*

Norwich is the nearest town to the station (0.6 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter April 30only 1 spring in 10 still has a frost later
  • Typical last frostApril 1450% chance of a frost after it
  • Typical first fall frostOctober 2450% chance of a frost before it
  • Frost-free season192 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season near Norwich, CTSpring: a frost after April 1 in 9 years out of 10, after April 14 in half of the years, after April 30 in 1 year out of 10. Fall: the first frost comes before October 9 in 1 year out of 10, before October 24 in half of the years, before November 7 in 9 years out of 10. Typical frost-free season: 192 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 14First frost ~Oct 24Frost season near Norwich, CTSpring: a frost after April 1 in 9 years out of 10, after April 14 in half of the years, after April 30 in 1 year out of 10. Fall: the first frost comes before October 9 in 1 year out of 10, before October 24 in half of the years, before November 7 in 9 years out of 10. Typical frost-free season: 192 days.JFMAMJJASONDLast frost ~Apr 14First frost ~Oct 24
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)April 30October 9
50% (typical)April 14October 24
90% (likely)April 1November 7
Frost-free season (32°F, 50% chance)
192 days
Hard frost (28°F), last in spring, 50% chance after
April 1
Hard frost (28°F), first in fall, 50% chance before
November 5

The last 15 years (2006–2020 normals)

Typical last frost April 11 (3 days earlier than the 30-year normal), typical first fall frost October 29 (5 days later). Frost-free season 199 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 near Norwich: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 30, 20% April 24, 30% April 21, 40% April 18, 50% April 14, 60% April 11, 70% April 9, 80% April 6, 90% April 1. Observed last spring frost in recent years: 2021 April 5, 2022 March 31, 2023 April 11, 2024 March 25, 2025 April 19, 2026 April 22.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 30Apr 14Apr 12021: April 52022: March 312023: April 112024: March 252025: April 192026: April 22Fall near Norwich: chance of a frost before this dateFall, chance of a frost before the date: 10% October 9, 20% October 13, 30% October 17, 40% October 20, 50% October 24, 60% October 27, 70% October 31, 80% November 3, 90% November 7. Observed first fall frost in recent years: 2021 November 4, 2022 October 30, 2023 November 2, 2024 November 4, 2025 October 27.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 9Oct 24Nov 72021: November 42022: October 302023: November 22024: November 42025: October 27
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 5November 4
2022March 31October 30
2023April 11November 2
2024March 25November 4
2025April 19October 27
2026April 22season not over yet

What these dates mean

Setting out tender crops on the early spring date of April 1 carries a 90 % chance of a frost later and is therefore a gamble for gardeners in the Norwich area.

The light-frost 50 % date of April 14 marks the point where the odds of a frost later are even, while the fall light-frost 50 % date of October 24 marks the point where the odds of a frost earlier are even. A cautious planting schedule uses the April 30 date, which has only a 10 % chance of a later frost, and the October 9 date, which has only a 10 % chance of an earlier frost, to minimize risk. The hard-frost 50 % dates are April 1 and November 5.

Hard frost at 28 °F can injure plant tissue that would survive a light frost at 32 °F.

How to read the probabilities

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

  • Spring: "10% after April 30" 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 9" 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 Norwich, CTNumbered nearest stations: 1 — Storrs, CT — 20 mi; 2 — Kingston, RI — 27 mi; 3 — North Foster, RI — 29 mi; 4 — Hartford (Brainard Field), CT — 34 mi; 5 — near Providence, RI — 35 mi.CTMARI25 mi · 40 km1. Storrs, CT — 20 mi12. Kingston, RI — 27 mi23. North Foster, RI — 29 mi34. Hartford (Brainard Field), CT — 34 mi45. near Providence, RI — 35 mi5
  1. Storrs, CT 20 mi (33 km)
  2. Kingston, RI 27 mi (44 km)
  3. North Foster, RI 29 mi (46 km)
  4. Hartford (Brainard Field), CT 34 mi (54 km)
  5. near Providence, RI 35 mi (57 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: 41.5267, -72.0653.