U.S. Frost Dates by Weather Station

NOAA station USC00398652 · South Dakota

Frost Dates for Victor, SD

NOAA weather station Victor 4 N (USC00398652), South Dakota · elevation 1095 ft (334 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 17only 1 spring in 10 still has a frost later
  • Typical last frostMay 450% 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 Victor, SDSpring: a frost after April 21 in 9 years out of 10, after May 4 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before September 21 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: 152 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 4First frost ~Oct 3Frost season at Victor, SDSpring: a frost after April 21 in 9 years out of 10, after May 4 in half of the years, after May 17 in 1 year out of 10. Fall: the first frost comes before September 21 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: 152 days.JFMAMJJASONDLast frost ~May 4First 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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 17September 21
50% (typical)May 4October 3
90% (likely)April 21October 17
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 14

The last 15 years (2006–2020 normals)

Typical last frost May 4 (same as the 30-year normal), typical first fall frost October 8 (5 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 Victor: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 17, 20% May 12, 30% May 9, 40% May 6, 50% May 4, 60% May 2, 70% April 30, 80% April 26, 90% April 21. Observed last spring frost in recent years: 2021 May 11, 2022 May 1, 2023 May 2, 2024 April 25, 2025 April 30, 2026 May 9.Spring: last frostChance of a frost after this date10%50%90%May 1May 17May 4Apr 212021: May 112022: May 12023: May 22024: April 252025: April 302026: May 9Fall at Victor: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 26, 30% September 29, 40% October 1, 50% October 3, 60% October 6, 70% October 9, 80% October 12, 90% October 17. Observed first fall frost in recent years: 2021 October 21, 2022 October 7, 2023 October 7, 2024 October 15, 2025 October 22.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 21Oct 3Oct 172021: October 212022: October 72023: October 72024: October 152025: 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 11October 21
2022May 1October 7
2023May 2October 7
2024April 25October 15
2025April 30October 22
2026May 9season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Victor is September 21, when there is only a 10% chance that a light frost has arrived. Counting on tender crops this late, as on October 17, carries a 90% chance of a frost and is a gamble.

The 50% light-frost dates—May 4 in spring and October 3 in fall—mean there is a 50% chance of a light frost later than May 4 and a 50% chance of a light frost earlier than October 3; they are not frost events but give a median reference for planning. The median hard-frost dates are April 24 and October 14.

For tender crops the cautious spring date is May 17 (10% chance of a later frost) and the cautious fall date is September 21 (10% chance of an earlier frost). A hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, so the hard-frost dates provide an additional risk indicator.

How to read the probabilities

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

  • Spring: "10% after May 17" 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 21" 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 Victor, SDNumbered nearest stations: 1 — Wheaton, MN — 18 mi; 2 — Sisseton, SD — 20 mi; 3 — Browns Valley, MN — 22 mi; 4 — Forman, ND — 38 mi; 5 — McLeod, ND — 38 mi.MNNDSD25 mi · 40 km1. Wheaton, MN — 18 mi12. Sisseton, SD — 20 mi23. Browns Valley, MN — 22 mi34. Forman, ND — 38 mi45. McLeod, ND — 38 mi5
  1. Wheaton, MN 18 mi (28 km)
  2. Sisseton, SD 20 mi (33 km)
  3. Browns Valley, MN 22 mi (36 km)
  4. Forman, ND 38 mi (60 km)
  5. McLeod, ND 38 mi (61 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: 45.9203, -96.8308.