U.S. Frost Dates by Weather Station

NOAA station USW00014752 · Connecticut

Frost Dates for Hartford (Brainard Field), CT

NOAA weather station Hartford Brainard Field (USW00014752), Connecticut · elevation 19 ft (6 m) · hardiness zone 7a*

  • Lower-risk planting dateafter May 1only 1 spring in 10 still has a frost later
  • Typical last frostApril 1750% chance of a frost after it
  • Typical first fall frostOctober 2650% chance of a frost before it
  • Frost-free season191 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season at Hartford (Brainard Field), CTSpring: a frost after April 1 in 9 years out of 10, after April 17 in half of the years, after May 1 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 26 in half of the years, before November 7 in 9 years out of 10. Typical frost-free season: 191 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 17First frost ~Oct 26Frost season at Hartford (Brainard Field), CTSpring: a frost after April 1 in 9 years out of 10, after April 17 in half of the years, after May 1 in 1 year out of 10. Fall: the first frost comes before October 12 in 1 year out of 10, before October 26 in half of the years, before November 7 in 9 years out of 10. Typical frost-free season: 191 days.JFMAMJJASONDLast frost ~Apr 17First frost ~Oct 26
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 1October 12
50% (typical)April 17October 26
90% (likely)April 1November 7
Frost-free season (32°F, 50% chance)
191 days
Hard frost (28°F), last in spring, 50% chance after
April 3
Hard frost (28°F), first in fall, 50% chance before
November 5

The last 15 years (2006–2020 normals)

Typical last frost April 15 (2 days earlier than the 30-year normal), typical first fall frost October 28 (2 days later). Frost-free season 194 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 Hartford (Brainard Field): chance of a frost after this dateSpring, chance of a frost after the date: 10% May 1, 20% April 27, 30% April 23, 40% April 20, 50% April 17, 60% April 14, 70% April 11, 80% April 6, 90% April 1. Observed last spring frost in recent years: 2021 April 4, 2022 April 18, 2023 April 9, 2024 April 8, 2025 April 18, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 1Apr 17Apr 12021: April 42022: April 182023: April 92024: April 82025: April 182026: April 21Fall at Hartford (Brainard Field): chance of a frost before this dateFall, chance of a frost before the date: 10% October 12, 20% October 16, 30% October 20, 40% October 23, 50% October 26, 60% October 29, 70% November 1, 80% November 3, 90% November 7. Observed first fall frost in recent years: 2021 November 4, 2022 October 29, 2023 November 2, 2024 November 3.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 12Oct 26Nov 72021: November 42022: October 292023: November 22024: 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 4November 4
2022April 18October 29
2023April 9November 2
2024April 8November 3
2025April 18incomplete record
2026April 21season 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 than that date, making it a gamble for gardeners in Hartford (Brainard Field). The 50% date in spring is April 17; this marks the point where a frost is equally likely to occur later or not, helping a grower gauge risk. A cautious plan would wait until the May 1 date, which has only a 10% chance of a frost later than it.

In fall the 50% date is October 26, and the cautious date to finish harvesting tender crops is October 12, with a 10% chance of a frost earlier than that date; counting on crops until November 7 would be a gamble with a 90% chance of frost earlier than that date. The hard-frost 50% dates are April 3 in spring and November 5. A hard frost at 28 °F can damage plants that 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 May 1" 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 12" 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 Hartford (Brainard Field), CTNumbered nearest stations: 1 — Hartford (Bradley Airport), CT — 14 mi; 2 — Bakersville, CT — 20 mi; 3 — Storrs, CT — 22 mi; 4 — near Norwich, CT — 34 mi; 5 — Norfolk, CT — 34 mi.CTMANYRI25 mi · 40 km1. Hartford (Bradley Airport), CT — 14 mi12. Bakersville, CT — 20 mi23. Storrs, CT — 22 mi34. near Norwich, CT — 34 mi45. Norfolk, CT — 34 mi5
  1. Hartford (Bradley Airport), CT 14 mi (23 km)
  2. Bakersville, CT 20 mi (32 km)
  3. Storrs, CT 22 mi (36 km)
  4. near Norwich, CT 34 mi (54 km)
  5. Norfolk, CT 34 mi (54 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 41.7361, -72.6506.