U.S. Frost Dates by Weather Station

NOAA station USC00256385 · Nebraska

Frost Dates for Oshkosh, NE

NOAA weather station Oshkosh (USC00256385), Nebraska · elevation 3390 ft (1033 m) · hardiness zone 5a*

  • Lower-risk planting dateafter May 22only 1 spring in 10 still has a frost later
  • Typical last frostMay 950% chance of a frost after it
  • Typical first fall frostOctober 250% chance of a frost before it
  • Frost-free season144 daystypical year, 32°F
  • Hardiness zone5acalculated*

The year at a glance

Frost season at Oshkosh, NESpring: a frost after April 28 in 9 years out of 10, after May 9 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 2 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 144 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 9First frost ~Oct 2Frost season at Oshkosh, NESpring: a frost after April 28 in 9 years out of 10, after May 9 in half of the years, after May 22 in 1 year out of 10. Fall: the first frost comes before September 20 in 1 year out of 10, before October 2 in half of the years, before October 14 in 9 years out of 10. Typical frost-free season: 144 days.JFMAMJJASONDLast frost ~May 9First frost ~Oct 2
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 28 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 22September 20
50% (typical)May 9October 2
90% (likely)April 28October 14
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 10

The last 15 years (2006–2020 normals)

Typical last frost May 9 (same as the 30-year normal), typical first fall frost October 3 (1 day later). Frost-free season 145 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 Oshkosh: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 22, 20% May 17, 30% May 14, 40% May 11, 50% May 9, 60% May 7, 70% May 4, 80% May 2, 90% April 28. Observed last spring frost in recent years: 2021 May 12, 2022 May 22, 2023 May 2, 2024 May 4, 2025 May 3, 2026 May 7.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 22May 9Apr 282021: May 122022: May 222023: May 22024: May 42025: May 32026: May 7Fall at Oshkosh: chance of a frost before this dateFall, chance of a frost before the date: 10% September 20, 20% September 24, 30% September 28, 40% September 30, 50% October 2, 60% October 4, 70% October 7, 80% October 10, 90% October 14. Observed first fall frost in recent years: 2021 October 14, 2022 October 8, 2023 October 7, 2024 October 1.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 20Oct 2Oct 142021: October 142022: October 82023: October 72024: October 1
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 14
2022May 22October 8
2023May 2October 7
2024May 4October 1
2025May 3incomplete record
2026May 7season not over yet

What these dates mean

The 144 days between the 50% dates of May 9 and October 2 in Oshkosh define the core growing window for tender crops; during this span a gardener can expect an even chance of a light frost on either side of the dates.

In spring the cautious date for setting out tender crops is May 22, which carries only a 10 % chance that a light frost will occur later, while planting on April 28 would be a gamble with a 90 % chance of frost later. In fall the cautious date to finish harvesting tender crops is September 20, with only a 10 % chance that a light frost has arrived earlier; waiting until October 14 would be a gamble with a 90 % chance of frost earlier. Hard frost at 28 °F, with median dates April 30 and October 10, matters more than a light frost because it can damage plants that survive a light frost.

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 20" 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 Oshkosh, NENumbered nearest stations: 1 — Lodgepole, NE — 23 mi; 2 — Arthur, NE — 36 mi; 3 — Kingsley Dam, NE — 37 mi; 4 — Ogallala, NE — 38 mi; 5 — Sedgwick, CO — 38 mi.NECO25 mi · 40 km1. Lodgepole, NE — 23 mi12. Arthur, NE — 36 mi23. Kingsley Dam, NE — 37 mi34. Ogallala, NE — 38 mi45. Sedgwick, CO — 38 mi5
  1. Lodgepole, NE 23 mi (37 km)
  2. Arthur, NE 36 mi (58 km)
  3. Kingsley Dam, NE 37 mi (60 km)
  4. Ogallala, NE 38 mi (61 km)
  5. Sedgwick, CO 38 mi (61 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: 41.4014, -102.3464.