U.S. Frost Dates by Weather Station

NOAA station USC00375270 · Rhode Island

Frost Dates for North Foster, RI

NOAA weather station North Foster 1 E (USC00375270), Rhode Island · elevation 630 ft (192 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 9only 1 spring in 10 still has a frost later
  • Typical last frostApril 2550% chance of a frost after it
  • Typical first fall frostOctober 1950% chance of a frost before it
  • Frost-free season176 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at North Foster, RISpring: a frost after April 13 in 9 years out of 10, after April 25 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 19 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 176 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 25First frost ~Oct 19Frost season at North Foster, RISpring: a frost after April 13 in 9 years out of 10, after April 25 in half of the years, after May 9 in 1 year out of 10. Fall: the first frost comes before October 4 in 1 year out of 10, before October 19 in half of the years, before November 2 in 9 years out of 10. Typical frost-free season: 176 days.JFMAMJJASONDLast frost ~Apr 25First frost ~Oct 19
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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 9October 4
50% (typical)April 25October 19
90% (likely)April 13November 2
Frost-free season (32°F, 50% chance)
176 days
Hard frost (28°F), last in spring, 50% chance after
April 12
Hard frost (28°F), first in fall, 50% chance before
October 30

The last 15 years (2006–2020 normals)

Typical last frost April 24 (1 day earlier than the 30-year normal), typical first fall frost October 23 (4 days later). Frost-free season 181 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 North Foster: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 9, 20% May 4, 30% May 1, 40% April 28, 50% April 25, 60% April 23, 70% April 20, 80% April 17, 90% April 13. Observed last spring frost in recent years: 2021 April 23, 2022 April 29, 2023 May 18, 2024 April 26.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 9Apr 25Apr 132021: April 232022: April 292023: May 182024: April 26Fall at North Foster: chance of a frost before this dateFall, chance of a frost before the date: 10% October 4, 20% October 9, 30% October 13, 40% October 16, 50% October 19, 60% October 21, 70% October 25, 80% October 28, 90% November 2. Observed first fall frost in recent years: 2021 November 3, 2022 October 20, 2023 November 1, 2024 October 17.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 4Oct 19Nov 22021: November 32022: October 202023: November 12024: October 17
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 3
2022April 29October 20
2023May 18November 1
2024April 26October 17
2025incomplete recordno data
2026no dataseason not over yet

What these dates mean

May 9 is the cautious spring date for North Foster, Rhode Island, with only a 10 percent chance of a light frost later; it lets a gardener plan to set out tender crops with minimal risk.

The 50% spring date is April 25, indicating an even chance of a light frost, while the 50% fall date is October 19, indicating an even chance of a light frost in autumn. October 4 is the cautious fall date, carrying only a 10 percent chance of a light frost earlier, and it marks the time to finish harvesting tender crops. The median hard-frost dates are April 12 and October 30. A hard frost at 28 °F can damage plants more severely than 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 9" 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 4" 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 North Foster, RINumbered nearest stations: 1 — near Providence, RI — 18 mi; 2 — Storrs, CT — 26 mi; 3 — near Fiskdale, MA — 27 mi; 4 — Kingston, RI — 27 mi; 5 — near Norwich, CT — 29 mi.MACTNY25 mi · 40 km1. near Providence, RI — 18 mi12. Storrs, CT — 26 mi23. near Fiskdale, MA — 27 mi34. Kingston, RI — 27 mi45. near Norwich, CT — 29 mi5
  1. near Providence, RI 18 mi (29 km)
  2. Storrs, CT 26 mi (42 km)
  3. near Fiskdale, MA 27 mi (43 km)
  4. Kingston, RI 27 mi (44 km)
  5. near Norwich, CT 29 mi (46 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: 41.8564, -71.7333.