U.S. Frost Dates by Weather Station

NOAA station USC00141029 · Kansas

Frost Dates for Brewster, KS

NOAA weather station Brewster 4 W (USC00141029), Kansas · elevation 3440 ft (1049 m) · hardiness zone 5b*

  • Lower-risk planting dateafter May 25only 1 spring in 10 still has a frost later
  • Typical last frostMay 950% chance of a frost after it
  • Typical first fall frostOctober 450% chance of a frost before it
  • Frost-free season145 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Brewster, KSSpring: a frost after April 28 in 9 years out of 10, after May 9 in half of the years, after May 25 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 4 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 145 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 9First frost ~Oct 4Frost season at Brewster, KSSpring: a frost after April 28 in 9 years out of 10, after May 9 in half of the years, after May 25 in 1 year out of 10. Fall: the first frost comes before September 21 in 1 year out of 10, before October 4 in half of the years, before October 17 in 9 years out of 10. Typical frost-free season: 145 days.JFMAMJJASONDLast frost ~May 9First frost ~Oct 4
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 25September 21
50% (typical)May 9October 4
90% (likely)April 28October 17
Frost-free season (32°F, 50% chance)
145 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 15

The last 15 years (2006–2020 normals)

Typical last frost May 9 (same as the 30-year normal), typical first fall frost October 5 (1 day later). Frost-free season 148 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 Brewster: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 25, 20% May 19, 30% May 15, 40% May 12, 50% May 9, 60% May 7, 70% May 4, 80% May 1, 90% April 28. Observed last spring frost in recent years: 2021 May 13.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 25May 9Apr 282021: May 13Fall at Brewster: chance of a frost before this dateFall, chance of a frost before the date: 10% September 21, 20% September 25, 30% September 29, 40% October 1, 50% October 4, 60% October 6, 70% October 9, 80% October 13, 90% October 17. Observed first fall frost in recent years: 2021 October 15.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 21Oct 4Oct 172021: October 15
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
2022no datano data
2023no datano data
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

The 145 days between the 50% dates in Brewster frame the window when light frosts become less probable, allowing tender crops to be managed. May 9 is the 50% date, indicating a 50% chance of a light frost later than this date in spring, and October 4 is the 50% date, indicating a 50% chance of a light frost earlier than this date in fall.

For a cautious plan, the spring date to set out tender crops is May 25, which carries only a 10% chance of a later frost, while the fall date to finish harvesting tender crops is September 21, which carries only a 10% chance of an earlier frost. The hard-frost 50% dates are April 30 in spring and October 15 in fall; a hard frost can damage plants more severely than 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 25" 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 21" 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 Brewster, KSNumbered nearest stations: 1 — Goodland, KS — 14 mi; 2 — Colby, KS — 20 mi; 3 — Oakley, KS — 32 mi; 4 — Saint Francis, KS — 34 mi; 5 — Sharon Springs, KS — 36 mi.CONE25 mi · 40 km1. Goodland, KS — 14 mi12. Colby, KS — 20 mi23. Oakley, KS — 32 mi34. Saint Francis, KS — 34 mi45. Sharon Springs, KS — 36 mi5
  1. Goodland, KS 14 mi (22 km)
  2. Colby, KS 20 mi (33 km)
  3. Oakley, KS 32 mi (52 km)
  4. Saint Francis, KS 34 mi (54 km)
  5. Sharon Springs, KS 36 mi (59 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 39.3672, -101.4461.