U.S. Frost Dates by Weather Station

NOAA station USC00251200 · Nebraska

Frost Dates for Broken Bow, NE

NOAA weather station Broken Bow 2 W (USC00251200), Nebraska · elevation 2504 ft (763 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 24only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostOctober 150% chance of a frost before it
  • Frost-free season142 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Broken Bow, NESpring: a frost after April 28 in 9 years out of 10, after May 10 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before October 1 in half of the years, before October 12 in 9 years out of 10. Typical frost-free season: 142 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Oct 1Frost season at Broken Bow, NESpring: a frost after April 28 in 9 years out of 10, after May 10 in half of the years, after May 24 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before October 1 in half of the years, before October 12 in 9 years out of 10. Typical frost-free season: 142 days.JFMAMJJASONDLast frost ~May 10First 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.

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 24September 18
50% (typical)May 10October 1
90% (likely)April 28October 12
Frost-free season (32°F, 50% chance)
142 days
Hard frost (28°F), last in spring, 50% chance after
May 2
Hard frost (28°F), first in fall, 50% chance before
October 9

The last 15 years (2006–2020 normals)

Typical last frost May 11 (1 day later than the 30-year normal), typical first fall frost October 2 (1 day 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 Broken Bow: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 24, 20% May 20, 30% May 16, 40% May 13, 50% May 10, 60% May 7, 70% May 5, 80% May 2, 90% April 28. Observed last spring frost in recent years: 2021 May 13, 2022 May 23, 2023 May 4, 2024 April 30, 2025 May 4, 2026 May 3.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 24May 10Apr 282021: May 132022: May 232023: May 42024: April 302025: May 42026: May 3Fall at Broken Bow: chance of a frost before this dateFall, chance of a frost before the date: 10% September 18, 20% September 23, 30% September 26, 40% September 29, 50% October 1, 60% October 3, 70% October 6, 80% October 9, 90% October 12. Observed first fall frost in recent years: 2021 October 14, 2022 October 8, 2023 October 7, 2024 September 23, 2025 October 19.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 18Oct 1Oct 122021: October 142022: October 82023: October 72024: September 232025: October 19
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 14
2022May 23October 8
2023May 4October 7
2024April 30September 23
2025May 4October 19
2026May 3season not over yet

What these dates mean

Setting out tender crops on April 28 in Broken Bow carries a 90% chance of a light frost later that season, making it a high-risk gamble.

The 50% date is May 10, indicating a 50% chance of a light frost later in spring, while the 50% date is October 1, reflecting a 50% chance of a light frost earlier in fall. A cautious planting plan uses the May 24 date for tender crops in spring and the September 18 date for finishing them in fall, each representing only a 10% chance of a later or earlier frost respectively.

Hard frost, defined at 28 °F, is more damaging than a light frost at 32 °F because it can freeze plant tissues that survive milder temperatures. The median hard-frost dates are May 2 and October 9, reminding gardeners that temperatures below 28 °F pose a greater risk than the 32 °F light-frost thresholds.

How to read the probabilities

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

  • Spring: "10% after May 24" 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 18" 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 Broken Bow, NENumbered nearest stations: 1 — Anselmo, NE — 18 mi; 2 — Gothenburg, NE — 41 mi; 3 — Ravenna, NE — 47 mi; 4 — Stapleton, NE — 48 mi; 5 — near Lexington, NE — 49 mi.NE25 mi · 40 km1. Anselmo, NE — 18 mi12. Gothenburg, NE — 41 mi23. Ravenna, NE — 47 mi34. Stapleton, NE — 48 mi45. near Lexington, NE — 49 mi5
  1. Anselmo, NE 18 mi (30 km)
  2. Gothenburg, NE 41 mi (66 km)
  3. Ravenna, NE 47 mi (76 km)
  4. Stapleton, NE 48 mi (77 km)
  5. near Lexington, NE 49 mi (79 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: 41.4083, -99.675.