U.S. Frost Dates by Weather Station

NOAA station USC00395561 · South Dakota

Frost Dates for Miller, SD

NOAA weather station Miller (USC00395561), South Dakota · elevation 1576 ft (480 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 16only 1 spring in 10 still has a frost later
  • Typical last frostMay 350% chance of a frost after it
  • Typical first fall frostOctober 350% chance of a frost before it
  • Frost-free season152 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Miller, SDSpring: a frost after April 19 in 9 years out of 10, after May 3 in half of the years, after May 16 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 3 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 152 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 3First frost ~Oct 3Frost season at Miller, SDSpring: a frost after April 19 in 9 years out of 10, after May 3 in half of the years, after May 16 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 3 in half of the years, before October 18 in 9 years out of 10. Typical frost-free season: 152 days.JFMAMJJASONDLast frost ~May 3First frost ~Oct 3
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 16September 20
50% (typical)May 3October 3
90% (likely)April 19October 18
Frost-free season (32°F, 50% chance)
152 days
Hard frost (28°F), last in spring, 50% chance after
April 24
Hard frost (28°F), first in fall, 50% chance before
October 13

The last 15 years (2006–2020 normals)

Typical last frost May 5 (2 days later than the 30-year normal), typical first fall frost October 7 (4 days later). Frost-free season 155 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 Miller: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 16, 20% May 12, 30% May 9, 40% May 6, 50% May 3, 60% May 1, 70% April 29, 80% April 25, 90% April 19. Observed last spring frost in recent years: 2021 May 10, 2022 May 2, 2023 May 2, 2024 April 24, 2025 April 29, 2026 May 8.Spring: last frostChance of a frost after this date10%50%90%May 1May 16May 3Apr 192021: May 102022: May 22023: May 22024: April 242025: April 292026: May 8Fall at Miller: chance of a frost before this dateFall, chance of a frost before the date: 10% September 20, 20% September 25, 30% September 28, 40% October 1, 50% October 3, 60% October 6, 70% October 10, 80% October 14, 90% October 18. Observed first fall frost in recent years: 2021 October 21, 2022 October 6, 2024 October 13, 2025 October 22.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 20Oct 3Oct 182021: October 212022: October 62024: October 132025: October 22
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 10October 21
2022May 2October 6
2023May 2incomplete record
2024April 24October 13
2025April 29October 22
2026May 8season not over yet

What these dates mean

May 16 is the cautious spring date for Miller; with only a ten percent chance of a light frost after that day, a gardener can plan to set out tender crops. The fifty-percent light-frost dates—May 3 in spring and October 3 in fall—mark the point where a light frost is equally likely to occur before or after, giving a neutral reference for timing decisions. The hard-frost median dates, April 24 and October 13, show when a 28 °F frost has even odds of happening, indicating a more severe risk. September 20 is the cautious fall date, providing a ten percent chance of a light frost earlier and allowing a gardener to finish harvesting tender crops. Because a hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F, it poses a greater threat.

How to read the probabilities

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

  • Spring: "10% after May 16" 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 20" 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 Miller, SDNumbered nearest stations: 1 — Highmore, SD — 23 mi; 2 — Faulkton, SD — 37 mi; 3 — Wessington Springs, SD — 37 mi; 4 — Huron, SD — 38 mi; 5 — Mellette, SD — 48 mi.25 mi · 40 km1. Highmore, SD — 23 mi12. Faulkton, SD — 37 mi23. Wessington Springs, SD — 37 mi34. Huron, SD — 38 mi45. Mellette, SD — 48 mi5
  1. Highmore, SD 23 mi (38 km)
  2. Faulkton, SD 37 mi (59 km)
  3. Wessington Springs, SD 37 mi (59 km)
  4. Huron, SD 38 mi (62 km)
  5. Mellette, SD 48 mi (78 km)

Sources

* Hardiness zone 4b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 44.5178, -98.9814.