U.S. Frost Dates by Weather Station

NOAA station USC00393069 · South Dakota

Frost Dates near Sturgis, SD

NOAA weather station Fort Meade (USC00393069), South Dakota · elevation 3308 ft (1008 m) · hardiness zone 5a*

Sturgis is the nearest town to the station (1.6 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter May 21only 1 spring in 10 still has a frost later
  • Typical last frostMay 850% chance of a frost after it
  • Typical first fall frostOctober 350% chance of a frost before it
  • Frost-free season147 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season near Sturgis, SDSpring: a frost after April 26 in 9 years out of 10, after May 8 in half of the years, after May 21 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 3 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 147 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 8First frost ~Oct 3Frost season near Sturgis, SDSpring: a frost after April 26 in 9 years out of 10, after May 8 in half of the years, after May 21 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 3 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 147 days.JFMAMJJASONDLast frost ~May 8First 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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 21September 19
50% (typical)May 8October 3
90% (likely)April 26October 17
Frost-free season (32°F, 50% chance)
147 days
Hard frost (28°F), last in spring, 50% chance after
April 28
Hard frost (28°F), first in fall, 50% chance before
October 13

The last 15 years (2006–2020 normals)

Typical last frost May 8 (same as the 30-year normal), typical first fall frost October 3. Frost-free season 146 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 near Sturgis: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 21, 20% May 17, 30% May 14, 40% May 11, 50% May 8, 60% May 5, 70% May 2, 80% April 30, 90% April 26. Observed last spring frost in recent years: 2021 May 11, 2022 May 23, 2023 May 8, 2024 May 4, 2025 April 29, 2026 May 20.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 21May 8Apr 262021: May 112022: May 232023: May 82024: May 42025: April 292026: May 20Fall near Sturgis: chance of a frost before this dateFall, chance of a frost before the date: 10% September 19, 20% September 23, 30% September 28, 40% October 1, 50% October 3, 60% October 5, 70% October 8, 80% October 12, 90% October 17. Observed first fall frost in recent years: 2021 October 12, 2022 October 18, 2023 October 6, 2024 October 13, 2025 October 13.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 19Oct 3Oct 172021: October 122022: October 182023: October 62024: October 132025: October 13
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 12
2022May 23October 18
2023May 8October 6
2024May 4October 13
2025April 29October 13
2026May 20season not over yet

What these dates mean

The growing window in the Sturgis area spans 147 days between the 50% light-frost dates of May 8 and October 3, a period when average temperatures normally remain above 32 °F.

In this location the 50% dates simply mark the point where a frost is equally likely to occur later (spring) or earlier (fall). For a cautious spring plan, the tender-crop date is May 21, which carries only a 10 % chance of a frost occurring later. In the fall, the cautious date to finish harvesting tender crops is September 19, with just a 10 % chance that a frost has already arrived. Planting on April 26 or waiting until October 17 would be a gamble, as each carries a 90 % chance of a frost in the opposite direction.

A hard frost at 28 °F is more damaging than a light 32 °F frost because it can injure plant tissue that survives 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 21" 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 19" 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 Sturgis, SDNumbered nearest stations: 1 — Lead, SD — 14 mi; 2 — Spearfish, SD — 20 mi; 3 — Newell, SD — 21 mi; 4 — near Blackhawk, SD — 22 mi; 5 — near Colonial Pine Hills, SD — 24 mi.SDWYMT25 mi · 40 km1. Lead, SD — 14 mi12. Spearfish, SD — 20 mi23. Newell, SD — 21 mi34. near Blackhawk, SD — 22 mi45. near Colonial Pine Hills, SD — 24 mi5
  1. Lead, SD 14 mi (22 km)
  2. Spearfish, SD 20 mi (33 km)
  3. Newell, SD 21 mi (34 km)
  4. near Blackhawk, SD 22 mi (36 km)
  5. near Colonial Pine Hills, SD 24 mi (39 km)

Sources

* Hardiness zone 5a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 44.4106, -103.4769.