U.S. Frost Dates by Weather Station

NOAA station USC00396054 · South Dakota

Frost Dates for Newell, SD

NOAA weather station Newell (USC00396054), South Dakota · elevation 2860 ft (872 m) · hardiness zone 4b*

  • Lower-risk planting dateafter May 22only 1 spring in 10 still has a frost later
  • Typical last frostMay 850% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season144 daystypical year, 32°F
  • Hardiness zone4bcalculated*

The year at a glance

Frost season at Newell, SDSpring: a frost after April 27 in 9 years out of 10, after May 8 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 1 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 144 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 8First frost ~Oct 1Frost season at Newell, SDSpring: a frost after April 27 in 9 years out of 10, after May 8 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 19 in 1 year out of 10, before October 1 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 144 days.JFMAMJJASONDLast frost ~May 8First frost ~Oct 1
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.Today

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 22September 19
50% (typical)May 8October 1
90% (likely)April 27October 15
Frost-free season (32°F, 50% chance)
144 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 11

The last 15 years (2006–2020 normals)

Typical last frost May 9 (1 day later than the 30-year normal), typical first fall frost October 4 (3 days later). 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 at Newell: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 22, 20% May 16, 30% May 13, 40% May 10, 50% May 8, 60% May 6, 70% May 3, 80% May 1, 90% April 27. Observed last spring frost in recent years: 2021 May 12, 2022 May 22, 2023 May 2, 2024 May 4, 2025 April 29, 2026 May 7.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 22May 8Apr 272021: May 122022: May 222023: May 22024: May 42025: April 292026: May 7Fall at Newell: chance of a frost before this dateFall, chance of a frost before the date: 10% September 19, 20% September 23, 30% September 27, 40% September 30, 50% October 1, 60% October 4, 70% October 7, 80% October 10, 90% October 15. Observed first fall frost in recent years: 2021 October 13, 2022 October 8, 2023 October 6, 2024 October 1, 2025 October 13.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 19Oct 1Oct 152021: October 132022: October 82023: October 62024: October 12025: 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 12October 13
2022May 22October 8
2023May 2October 6
2024May 4October 1
2025April 29October 13
2026May 7season not over yet

What these dates mean

May 22 is the cautious spring date for Newell; with only a 10 % chance of a light frost occurring later, it lets a gardener set out tender crops with minimal risk. The earlier May 8 date is the 50 % point, meaning an even chance of a frost later, and April 27 carries a 90 % chance, making an even earlier planting a gamble.

The 50 % dates—May 8 for spring and October 1 for fall—represent the median moment when a light frost is just as likely to appear as not, giving a clear reference for the middle of the risk window. September 19 is the cautious fall date, with only a 10 % chance that a light frost has already arrived, allowing the final harvest of tender crops. A hard frost at 28 °F can damage plants more severely than a light frost at 32 °F, so the April 30 and October 11 50 % hard-frost dates are important markers.

How to read the probabilities

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

  • Spring: "10% after May 22" 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 Newell, SDNumbered nearest stations: 1 — near Sturgis, SD — 21 mi; 2 — Belle Fourche, SD — 21 mi; 3 — Spearfish, SD — 27 mi; 4 — Lead, SD — 29 mi; 5 — near Blackhawk, SD — 42 mi.SDWYMT25 mi · 40 km1. near Sturgis, SD — 21 mi12. Belle Fourche, SD — 21 mi23. Spearfish, SD — 27 mi34. Lead, SD — 29 mi45. near Blackhawk, SD — 42 mi5
  1. near Sturgis, SD 21 mi (34 km)
  2. Belle Fourche, SD 21 mi (34 km)
  3. Spearfish, SD 27 mi (43 km)
  4. Lead, SD 29 mi (47 km)
  5. near Blackhawk, SD 42 mi (67 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: 44.7136, -103.4258.