U.S. Frost Dates by Weather Station

NOAA station USC00258320 · Nebraska

Frost Dates for Superior, NE

NOAA weather station Superior (USC00258320), Nebraska · elevation 1512 ft (461 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 10only 1 spring in 10 still has a frost later
  • Typical last frostApril 2950% chance of a frost after it
  • Typical first fall frostOctober 1050% chance of a frost before it
  • Frost-free season162 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Superior, NESpring: a frost after April 15 in 9 years out of 10, after April 29 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before September 26 in 1 year out of 10, before October 10 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 162 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 29First frost ~Oct 10Frost season at Superior, NESpring: a frost after April 15 in 9 years out of 10, after April 29 in half of the years, after May 10 in 1 year out of 10. Fall: the first frost comes before September 26 in 1 year out of 10, before October 10 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 162 days.JFMAMJJASONDLast frost ~Apr 29First frost ~Oct 10
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 25 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 10September 26
50% (typical)April 29October 10
90% (likely)April 15October 22
Frost-free season (32°F, 50% chance)
162 days
Hard frost (28°F), last in spring, 50% chance after
April 19
Hard frost (28°F), first in fall, 50% chance before
October 19

The last 15 years (2006–2020 normals)

Typical last frost April 30 (1 day later than the 30-year normal), typical first fall frost October 15 (5 days later). Frost-free season 168 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 Superior: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 10, 20% May 6, 30% May 3, 40% May 1, 50% April 29, 60% April 26, 70% April 23, 80% April 20, 90% April 15. Observed last spring frost in recent years: 2021 May 13, 2022 May 22, 2024 April 22, 2025 April 21, 2026 May 2.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 10Apr 29Apr 152021: May 132022: May 222024: April 222025: April 212026: May 2Fall at Superior: chance of a frost before this dateFall, chance of a frost before the date: 10% September 26, 20% September 30, 30% October 3, 40% October 7, 50% October 10, 60% October 13, 70% October 15, 80% October 18, 90% October 22. Observed first fall frost in recent years: 2021 October 15, 2023 October 7, 2024 October 14, 2025 October 22.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 26Oct 10Oct 222021: October 152023: October 72024: October 142025: 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 13October 15
2022May 22incomplete record
2023incomplete recordOctober 7
2024April 22October 14
2025April 21October 22
2026May 2season not over yet

What these dates mean

May 10 is the cautious spring date for light frost, and it lets a gardener set out tender crops when only a 10% chance remains that a frost will occur later.

The 50% spring date of April 29 and the 50% fall date of October 10 each represent the median point at which a light frost is equally likely to have happened or not; they give a reference for when the risk is balanced. The hard-frost median dates are April 19 in spring and October 19 in fall, and the period between the two 32°F 50% dates spans 162 days.

September 26 is the cautious fall date for light frost, and it provides a deadline to finish harvesting tender crops with only a 10% chance that a frost has arrived earlier. A hard frost at 28°F can damage plants that survive a light frost at 32°F, so it represents a higher level of risk.

How to read the probabilities

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

  • Spring: "10% after May 10" 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 26" 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 Superior, NENumbered nearest stations: 1 — Red Cloud, NE — 24 mi; 2 — Belleville, KS — 27 mi; 3 — Hebron, NE — 28 mi; 4 — Clay Center, NE — 34 mi; 5 — Beloit, KS — 40 mi.25 mi · 40 km1. Red Cloud, NE — 24 mi12. Belleville, KS — 27 mi23. Hebron, NE — 28 mi34. Clay Center, NE — 34 mi45. Beloit, KS — 40 mi5
  1. Red Cloud, NE 24 mi (39 km)
  2. Belleville, KS 27 mi (44 km)
  3. Hebron, NE 28 mi (44 km)
  4. Clay Center, NE 34 mi (55 km)
  5. Beloit, KS 40 mi (64 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.0297, -98.0758.