U.S. Frost Dates by Weather Station

NOAA station USC00251575 · Nebraska

Frost Dates for Chadron, NE

NOAA weather station Chadron 3 SW (USC00251575), Nebraska · elevation 3383 ft (1031 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 31only 1 spring in 10 still has a frost later
  • Typical last frostMay 1550% chance of a frost after it
  • Typical first fall frostSeptember 2850% chance of a frost before it
  • Frost-free season133 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Chadron, NESpring: a frost after May 2 in 9 years out of 10, after May 15 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 13 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: 133 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 15First frost ~Sep 28Frost season at Chadron, NESpring: a frost after May 2 in 9 years out of 10, after May 15 in half of the years, after May 31 in 1 year out of 10. Fall: the first frost comes before September 13 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: 133 days.JFMAMJJASONDLast frost ~May 15First 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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 31September 13
50% (typical)May 15September 28
90% (likely)May 2October 11
Frost-free season (32°F, 50% chance)
133 days
Hard frost (28°F), last in spring, 50% chance after
May 5
Hard frost (28°F), first in fall, 50% chance before
October 7

The last 15 years (2006–2020 normals)

Typical last frost May 17 (2 days later than the 30-year normal), typical first fall frost September 25 (3 days earlier). Frost-free season 130 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 Chadron: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 31, 20% May 25, 30% May 21, 40% May 18, 50% May 15, 60% May 13, 70% May 10, 80% May 6, 90% May 2. Observed last spring frost in recent years: 2021 May 13, 2022 May 25, 2023 May 2, 2024 June 19, 2025 May 17, 2026 June 15.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 31May 15May 22021: May 132022: May 252023: May 22024: June 192025: May 172026: June 15Fall at Chadron: chance of a frost before this dateFall, chance of a frost before the date: 10% September 13, 20% September 19, 30% September 22, 40% September 25, 50% September 28, 60% October 1, 70% October 3, 80% October 6, 90% October 11. Observed first fall frost in recent years: 2021 October 3, 2022 October 8, 2023 October 6, 2024 September 22, 2025 September 6.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 13Sep 28Oct 112021: October 32022: October 82023: October 62024: September 222025: September 6
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 13October 3
2022May 25October 8
2023May 2October 6
2024June 19September 22
2025May 17September 6
2026June 15season not over yet

What these dates mean

May 31 is the cautious spring date for light frost, with only a 10% chance that a frost occurs later, and it gives a gardener a window to set out tender crops. The 50% date is May 15, meaning that on that day there is an even chance of a light frost occurring later in spring. Setting seedlings earlier, such as on May 2, carries a 90% chance of a frost and is therefore a gamble.

In fall, September 13 is the cautious date, with a 10% chance that a light frost has already arrived, making it the date to finish harvesting tender crops. The 50% date is September 28, indicating an even odds point for a frost earlier in autumn. Hard frost, measured at 28°F, can injury plants more severely than a light frost; the median hard-frost dates are May 5 and October 7.

How to read the probabilities

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

  • Spring: "10% after May 31" 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 13" 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 Chadron, NENumbered nearest stations: 1 — Oelrichs, SD — 28 mi; 2 — Oral, SD — 43 mi; 3 — Harrison, NE — 43 mi; 4 — Gordon, NE — 44 mi; 5 — Hot Springs, SD — 48 mi.SDWY25 mi · 40 km1. Oelrichs, SD — 28 mi12. Oral, SD — 43 mi23. Harrison, NE — 43 mi34. Gordon, NE — 44 mi45. Hot Springs, SD — 48 mi5
  1. Oelrichs, SD 28 mi (45 km)
  2. Oral, SD 43 mi (68 km)
  3. Harrison, NE 43 mi (69 km)
  4. Gordon, NE 44 mi (70 km)
  5. Hot Springs, SD 48 mi (78 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: 42.8083, -103.0533.