U.S. Frost Dates by Weather Station

NOAA station USC00200710 · Michigan

Frost Dates for Benton Harbor, MI

NOAA weather station Benton Harbor Airport (USC00200710), Michigan · elevation 625 ft (191 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 26only 1 spring in 10 still has a frost later
  • Typical last frostMay 550% chance of a frost after it
  • Typical first fall frostOctober 1550% chance of a frost before it
  • Frost-free season161 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Benton Harbor, MISpring: a frost after April 20 in 9 years out of 10, after May 5 in half of the years, after May 26 in 1 year out of 10. Fall: the first frost comes before September 28 in 1 year out of 10, before October 15 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 161 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 5First frost ~Oct 15Frost season at Benton Harbor, MISpring: a frost after April 20 in 9 years out of 10, after May 5 in half of the years, after May 26 in 1 year out of 10. Fall: the first frost comes before September 28 in 1 year out of 10, before October 15 in half of the years, before November 1 in 9 years out of 10. Typical frost-free season: 161 days.JFMAMJJASONDLast frost ~May 5First frost ~Oct 15
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 26September 28
50% (typical)May 5October 15
90% (likely)April 20November 1
Frost-free season (32°F, 50% chance)
161 days
Hard frost (28°F), last in spring, 50% chance after
April 25
Hard frost (28°F), first in fall, 50% chance before
October 30

The last 15 years (2006–2020 normals)

Typical last frost May 2 (3 days earlier than the 30-year normal), typical first fall frost October 21 (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 Benton Harbor: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 26, 20% May 19, 30% May 14, 40% May 9, 50% May 5, 60% May 2, 70% April 30, 80% April 26, 90% April 20. Observed last spring frost in recent years: 2021 May 14, 2022 June 3, 2023 May 3, 2024 April 25, 2025 April 28, 2026 May 13.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 26May 5Apr 202021: May 142022: June 32023: May 32024: April 252025: April 282026: May 13Fall at Benton Harbor: chance of a frost before this dateFall, chance of a frost before the date: 10% September 28, 20% October 4, 30% October 8, 40% October 11, 50% October 15, 60% October 18, 70% October 22, 80% October 26, 90% November 1. Observed first fall frost in recent years: 2021 October 27, 2022 October 27, 2023 October 31, 2024 November 2, 2025 November 9.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 28Oct 15Nov 12021: October 272022: October 272023: October 312024: November 22025: November 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 14October 27
2022June 3October 27
2023May 3October 31
2024April 25November 2
2025April 28November 9
2026May 13season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Benton Harbor is September 28, when there is only a 10% chance that a light frost has arrived. For a gardener, the 50% light-frost date of May 5 signals an even chance of a frost occurring later in spring, and the 50% light-frost date of October 15 signals an even chance of a frost having arrived earlier in fall. The hard-frost median dates are April 25 in spring and October 30 in fall.

A cautious planting plan therefore uses the May 26 date in spring, which carries a 10% chance of a frost later, and the September 28 date in fall, which carries a 10% chance of a frost earlier. Hard frost at 28 °F matters more than light frost at 32 °F because it can injure plants that would otherwise survive the milder temperature.

How to read the probabilities

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

  • Spring: "10% after May 26" 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 September 28" 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 Benton Harbor, MINumbered nearest stations: 1 — Dowagiac, MI — 18 mi; 2 — near South Bend, IN — 29 mi; 3 — Laporte, IN — 39 mi; 4 — Lakeville, IN — 42 mi; 5 — Three Rivers, MI — 43 mi.MI25 mi · 40 km1. Dowagiac, MI — 18 mi12. near South Bend, IN — 29 mi23. Laporte, IN — 39 mi34. Lakeville, IN — 42 mi45. Three Rivers, MI — 43 mi5
  1. Dowagiac, MI 18 mi (29 km)
  2. near South Bend, IN 29 mi (47 km)
  3. Laporte, IN 39 mi (62 km)
  4. Lakeville, IN 42 mi (68 km)
  5. Three Rivers, MI 43 mi (69 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: 42.1244, -86.4267.