U.S. Frost Dates by Weather Station

NOAA station USC00141351 · Kansas

Frost Dates for Cassoday, KS

NOAA weather station Cassoday 2 SE (USC00141351), Kansas · elevation 1520 ft (463 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 1850% chance of a frost after it
  • Typical first fall frostOctober 2250% chance of a frost before it
  • Frost-free season186 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Cassoday, KSSpring: a frost after April 2 in 9 years out of 10, after April 18 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 22 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 186 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 18First frost ~Oct 22Frost season at Cassoday, KSSpring: a frost after April 2 in 9 years out of 10, after April 18 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 6 in 1 year out of 10, before October 22 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 186 days.JFMAMJJASONDLast frost ~Apr 18First frost ~Oct 22
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 2October 6
50% (typical)April 18October 22
90% (likely)April 2November 4
Frost-free season (32°F, 50% chance)
186 days
Hard frost (28°F), last in spring, 50% chance after
April 7
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 17 (1 day earlier than the 30-year normal), typical first fall frost October 22. Frost-free season 189 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 Cassoday: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 28, 30% April 24, 40% April 21, 50% April 18, 60% April 14, 70% April 11, 80% April 7, 90% April 2. Observed last spring frost in recent years: 2021 April 22.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 2Apr 18Apr 22021: April 22Fall at Cassoday: chance of a frost before this dateFall, chance of a frost before the date: 10% October 6, 20% October 13, 30% October 17, 40% October 20, 50% October 22, 60% October 25, 70% October 28, 80% November 1, 90% November 4. Observed first fall frost in recent years: 2021 October 16.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 6Oct 22Nov 42021: October 16
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 16
2022incomplete recordno data
2023no datano data
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

Planting tender crops on April 2 in Cassoday is a gamble; there is a 90 % chance that a light frost will still occur later that season. By contrast, May 2 carries only a 10 % chance of a later frost and is considered the cautious date for setting out those sensitive plantings.

The 50 % light-frost dates are April 18 for spring and October 22 for fall; on each of those days the odds of a frost later (spring) or earlier (fall) are even. The 50 % hard-frost dates are April 7 in spring and November 1 in fall, marking the median points when temperatures reach 28 °F. Hard frosts can damage plants more severely because the colder temperature penetrates tissue more deeply.

For a low-risk schedule, gardeners should aim to place tender crops outdoors after May 2 in spring and to finish harvesting them by October 6 in fall. The probabilities reflect a 28-year record spanning 186 days between the two 32 °F 50 % dates.

How to read the probabilities

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

  • Spring: "10% after May 2" 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 October 6" 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 Cassoday, KSNumbered nearest stations: 1 — El Dorado, KS — 19 mi; 2 — Eureka, KS — 23 mi; 3 — Cottonwood Falls, KS — 24 mi; 4 — Emporia, KS — 35 mi; 5 — near Marion, KS — 36 mi.25 mi · 40 km1. El Dorado, KS — 19 mi12. Eureka, KS — 23 mi23. Cottonwood Falls, KS — 24 mi34. Emporia, KS — 35 mi45. near Marion, KS — 36 mi5
  1. El Dorado, KS 19 mi (31 km)
  2. Eureka, KS 23 mi (37 km)
  3. Cottonwood Falls, KS 24 mi (39 km)
  4. Emporia, KS 35 mi (56 km)
  5. near Marion, KS 36 mi (57 km)

Sources

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

Station coordinates: 38.0211, -96.6036.