U.S. Frost Dates by Weather Station

NOAA station USC00392927 · South Dakota

Frost Dates for Faulkton, SD

NOAA weather station Faulkton 1 NW (USC00392927), South Dakota · elevation 1597 ft (487 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 25only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostSeptember 2850% chance of a frost before it
  • Frost-free season139 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Faulkton, SDSpring: a frost after April 29 in 9 years out of 10, after May 10 in half of the years, after May 25 in 1 year out of 10. Fall: the first frost comes before September 15 in 1 year out of 10, before September 28 in half of the years, before October 11 in 9 years out of 10. Typical frost-free season: 139 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Sep 28Frost season at Faulkton, SDSpring: a frost after April 29 in 9 years out of 10, after May 10 in half of the years, after May 25 in 1 year out of 10. Fall: the first frost comes before September 15 in 1 year out of 10, before September 28 in half of the years, before October 11 in 9 years out of 10. Typical frost-free season: 139 days.JFMAMJJASONDLast frost ~May 10First frost ~Sep 28
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 25September 15
50% (typical)May 10September 28
90% (likely)April 29October 11
Frost-free season (32°F, 50% chance)
139 days
Hard frost (28°F), last in spring, 50% chance after
May 1
Hard frost (28°F), first in fall, 50% chance before
October 6

The last 15 years (2006–2020 normals)

Typical last frost May 9 (1 day earlier than the 30-year normal), typical first fall frost October 1 (3 days later). Frost-free season 144 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 Faulkton: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 25, 20% May 21, 30% May 17, 40% May 13, 50% May 10, 60% May 8, 70% May 5, 80% May 2, 90% April 29. Observed last spring frost in recent years: 2021 May 11, 2022 May 2, 2023 May 2, 2024 April 24, 2025 April 29.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 25May 10Apr 292021: May 112022: May 22023: May 22024: April 242025: April 29Fall at Faulkton: chance of a frost before this dateFall, chance of a frost before the date: 10% September 15, 20% September 19, 30% September 22, 40% September 25, 50% September 28, 60% October 1, 70% October 3, 80% October 7, 90% October 11. Observed first fall frost in recent years: 2021 October 21, 2022 September 28, 2023 October 7, 2024 October 14, 2025 October 14.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 15Sep 28Oct 112021: October 212022: September 282023: October 72024: October 142025: October 14
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 11October 21
2022May 2September 28
2023May 2October 7
2024April 24October 14
2025April 29October 14
2026incomplete recordseason not over yet

What these dates mean

Setting out tender crops on April 29 in Faulkton carries a 90% chance of a frost later, making it a gamble. The cautious spring date for tender crops is May 25, when only a 10% chance of a later frost remains.

The 50% date for light frost in spring is May 10; it represents an even-odds chance of a frost later than this point, while the 50% date for light frost in fall is September 28, marking an even-odds chance of a frost earlier than that day. For a cautious fall plan, September 15 is used, because only a 10% chance of an earlier frost exists. A hard frost at 28 °F can injure plants that would survive a 32 °F light frost, so the 50% hard-frost dates of May 1 and October 6 are especially significant for gardeners in this location.

How to read the probabilities

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

  • Spring: "10% after May 25" 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 15" 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 Faulkton, SDNumbered nearest stations: 1 — Mellette, SD — 28 mi; 2 — Ipswich, SD — 29 mi; 3 — Roscoe, SD — 30 mi; 4 — Miller, SD — 37 mi; 5 — Highmore, SD — 39 mi.25 mi · 40 km1. Mellette, SD — 28 mi12. Ipswich, SD — 29 mi23. Roscoe, SD — 30 mi34. Miller, SD — 37 mi45. Highmore, SD — 39 mi5
  1. Mellette, SD 28 mi (45 km)
  2. Ipswich, SD 29 mi (46 km)
  3. Roscoe, SD 30 mi (49 km)
  4. Miller, SD 37 mi (59 km)
  5. Highmore, SD 39 mi (63 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: 45.0364, -99.1342.