U.S. Frost Dates by Weather Station

NOAA station USC00201476 · Michigan

Frost Dates for Charlotte, MI

NOAA weather station Charlotte (USC00201476), Michigan · elevation 902 ft (275 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 18only 1 spring in 10 still has a frost later
  • Typical last frostMay 150% chance of a frost after it
  • Typical first fall frostOctober 1550% chance of a frost before it
  • Frost-free season164 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Charlotte, MISpring: a frost after April 19 in 9 years out of 10, after May 1 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 15 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 164 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 1First frost ~Oct 15Frost season at Charlotte, MISpring: a frost after April 19 in 9 years out of 10, after May 1 in half of the years, after May 18 in 1 year out of 10. Fall: the first frost comes before October 1 in 1 year out of 10, before October 15 in half of the years, before October 29 in 9 years out of 10. Typical frost-free season: 164 days.JFMAMJJASONDLast frost ~May 1First 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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 18October 1
50% (typical)May 1October 15
90% (likely)April 19October 29
Frost-free season (32°F, 50% chance)
164 days
Hard frost (28°F), last in spring, 50% chance after
April 20
Hard frost (28°F), first in fall, 50% chance before
October 28

The last 15 years (2006–2020 normals)

Typical last frost May 3 (2 days later than the 30-year normal), typical first fall frost October 18 (3 days later). Frost-free season 167 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 Charlotte: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 18, 20% May 12, 30% May 7, 40% May 5, 50% May 1, 60% April 29, 70% April 26, 80% April 22, 90% April 19.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 18May 1Apr 19Fall at Charlotte: chance of a frost before this dateFall, chance of a frost before the date: 10% October 1, 20% October 5, 30% October 8, 40% October 12, 50% October 15, 60% October 18, 70% October 21, 80% October 24, 90% October 29.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 1Oct 15Oct 29
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.

What these dates mean

May 18 is the cautious spring date for Charlotte, Michigan, with only a 10 % chance of a light frost later. This allows a gardener to set out tender crops with a low risk of frost damage.

The 50 % light-frost dates are May 1 in spring and October 15 in fall; each marks the point when a light frost has a 50 % chance of occurring. The cautious fall date is October 1, when there is only a 10 % chance that a light frost has already arrived, giving a reliable window to finish harvesting tender crops. Hard-frost dates are April 20 and October 28, and a hard frost can injure plants that survive a light frost, so it represents a higher danger. The analysis uses 29 years of NOAA data, and the span between the two 32°F 50 % dates is 164 days.

How to read the probabilities

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

  • Spring: "10% after May 18" 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 1" 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 Charlotte, MINumbered nearest stations: 1 — near Lansing, MI — 20 mi; 2 — Hastings, MI — 24 mi; 3 — near Jackson, MI — 27 mi; 4 — near Coldwater, MI — 42 mi; 5 — Hillsdale, MI — 44 mi.OH25 mi · 40 km1. near Lansing, MI — 20 mi12. Hastings, MI — 24 mi23. near Jackson, MI — 27 mi34. near Coldwater, MI — 42 mi45. Hillsdale, MI — 44 mi5
  1. near Lansing, MI 20 mi (33 km)
  2. Hastings, MI 24 mi (39 km)
  3. near Jackson, MI 27 mi (43 km)
  4. near Coldwater, MI 42 mi (67 km)
  5. Hillsdale, MI 44 mi (70 km)

Sources

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

Station coordinates: 42.55, -84.825.