U.S. Frost Dates by Weather Station

NOAA station USC00145852 · Kansas

Frost Dates for Norton Dam, KS

NOAA weather station Norton Dam (USC00145852), Kansas · elevation 2346 ft (715 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 15only 1 spring in 10 still has a frost later
  • Typical last frostMay 150% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season162 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Norton Dam, KSSpring: a frost after April 17 in 9 years out of 10, after May 1 in half of the years, after May 15 in 1 year out of 10. Fall: the first frost comes before September 29 in 1 year out of 10, before October 12 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 162 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 1First frost ~Oct 12Frost season at Norton Dam, KSSpring: a frost after April 17 in 9 years out of 10, after May 1 in half of the years, after May 15 in 1 year out of 10. Fall: the first frost comes before September 29 in 1 year out of 10, before October 12 in half of the years, before October 22 in 9 years out of 10. Typical frost-free season: 162 days.JFMAMJJASONDLast frost ~May 1First frost ~Oct 12
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 15September 29
50% (typical)May 1October 12
90% (likely)April 17October 22
Frost-free season (32°F, 50% chance)
162 days
Hard frost (28°F), last in spring, 50% chance after
April 21
Hard frost (28°F), first in fall, 50% chance before
October 21

The last 15 years (2006–2020 normals)

Typical last frost April 30 (1 day earlier than the 30-year normal), typical first fall frost October 15 (3 days later). Frost-free season 165 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 Norton Dam: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 15, 20% May 9, 30% May 5, 40% May 3, 50% May 1, 60% April 29, 70% April 26, 80% April 22, 90% April 17. Observed last spring frost in recent years: 2021 April 22, 2022 April 26, 2023 May 3, 2024 April 22, 2025 April 20, 2026 May 3.Spring: last frostChance of a frost after this date10%50%90%May 1May 15May 1Apr 172021: April 222022: April 262023: May 32024: April 222025: April 202026: May 3Fall at Norton Dam: chance of a frost before this dateFall, chance of a frost before the date: 10% September 29, 20% October 3, 30% October 6, 40% October 10, 50% October 12, 60% October 14, 70% October 17, 80% October 20, 90% October 22. Observed first fall frost in recent years: 2021 October 15, 2022 October 16, 2023 October 6, 2024 October 14, 2025 October 19.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 29Oct 12Oct 222021: October 152022: October 162023: October 62024: October 142025: 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
2021April 22October 15
2022April 26October 16
2023May 3October 6
2024April 22October 14
2025April 20October 19
2026May 3season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Norton Dam is September 29, when there is only a 10 % chance that a light frost has arrived.

For a gardener, the 50 % dates mark the point at which a light frost is equally likely to occur later (spring) or earlier (fall); they are May 1 for spring and October 12 for fall. The 50 % dates for hard frost are April 21 and October 21, indicating an even chance of reaching 28 °F on either side of those days. A cautious plan therefore uses the May 15 light-frost date, which carries a 10 % chance of a frost later, for setting out tender crops, and the September 29 light-frost date, also with a 10 % chance of an earlier frost, for ending the tender-crop harvest.

Because a hard frost at 28 °F can damage plant tissue that survives a light frost at 32 °F, it represents a greater risk to crops.

How to read the probabilities

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

  • Spring: "10% after May 15" 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 29" 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 Norton Dam, KSNumbered nearest stations: 1 — Norton, KS — 7 mi; 2 — Beaver City, NE — 23 mi; 3 — Cambridge, NE — 34 mi; 4 — Plainville, KS — 49 mi; 5 — Holdrege, NE — 53 mi.KSNE25 mi · 40 km1. Norton, KS — 7 mi12. Beaver City, NE — 23 mi23. Cambridge, NE — 34 mi34. Plainville, KS — 49 mi45. Holdrege, NE — 53 mi5
  1. Norton, KS 7 mi (12 km)
  2. Beaver City, NE 23 mi (37 km)
  3. Cambridge, NE 34 mi (55 km)
  4. Plainville, KS 49 mi (79 km)
  5. Holdrege, NE 53 mi (86 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: 39.8114, -99.9386.