U.S. Frost Dates by Weather Station

NOAA station USC00411048 · Texas

Frost Dates for Brenham, TX

NOAA weather station Brenham (USC00411048), Texas · elevation 313 ft (95 m) · hardiness zone 9a*

  • Lower-risk planting dateafter March 20only 1 spring in 10 still has a frost later
  • Typical last frostMarch 250% chance of a frost after it
  • Typical first fall frostNovember 3050% chance of a frost before it
  • Frost-free season273 daystypical year, 32°F
  • Hardiness zone9acalculated*

The year at a glance

Frost season at Brenham, TXSpring: a frost after January 31 in 9 years out of 10, after March 2 in half of the years, after March 20 in 1 year out of 10. Fall: the first frost comes before November 8 in 1 year out of 10, before November 30 in half of the years, before December 23 in 9 years out of 10. Typical frost-free season: 273 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 2First frost ~Nov 30Frost season at Brenham, TXSpring: a frost after January 31 in 9 years out of 10, after March 2 in half of the years, after March 20 in 1 year out of 10. Fall: the first frost comes before November 8 in 1 year out of 10, before November 30 in half of the years, before December 23 in 9 years out of 10. Typical frost-free season: 273 days.JFMAMJJASONDLast frost ~Mar 2First frost ~Nov 30
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)March 20November 8
50% (typical)March 2November 30
90% (likely)January 31December 23
Frost-free season (32°F, 50% chance)
273 days
Hard frost (28°F), last in spring, 50% chance after
February 10
Hard frost (28°F), first in fall, 50% chance before
December 18

The last 15 years (2006–2020 normals)

Typical last frost February 27 (3 days earlier than the 30-year normal), typical first fall frost December 1 (1 day later). Frost-free season 280 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 Brenham: chance of a frost after this dateSpring, chance of a frost after the date: 10% March 20, 20% March 14, 30% March 9, 40% March 5, 50% March 2, 60% February 27, 70% February 19, 80% February 12, 90% January 31. Observed last spring frost in recent years: 2024 January 21, 2025 February 21, 2026 February 2.Spring: last frostChance of a frost after this date10%50%90%Feb 1Mar 1Apr 1Mar 20Mar 2Jan 312024: January 212025: February 212026: February 2Fall at Brenham: chance of a frost before this dateFall, chance of a frost before the date: 10% November 8, 20% November 15, 30% November 21, 40% November 26, 50% November 30, 60% December 3, 70% December 8, 80% December 14, 90% December 23. Observed first fall frost in recent years: 2022 December 18, 2023 January 15, 2024 January 6, 2025 December 15.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Jan 1Nov 8Nov 30Dec 232022: December 182023: January 152024: January 62025: December 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
2021incomplete recordincomplete record
2022incomplete recordDecember 18
2023incomplete recordJanuary 15
2024January 21January 6
2025February 21December 15
2026February 2season not over yet

What these dates mean

The cautious fall date for finishing the harvest in Brenham is November 8, when there is only a 10 % chance that a light frost has arrived. The 50% light-frost dates are March 2 and November 30; each marks the point at which a gardener faces an even chance of a frost occurring. The 50% hard-frost dates are February 10 and December 18.

For tender crops in spring the cautious date is March 20, because only a 10 % chance of a frost later than that date is expected; planting earlier on January 31 carries a 90 % chance and is a gamble. In fall the cautious date is November 8, while waiting until December 23 would involve a 90 % chance of an earlier frost. A hard frost at 28 °F is more damaging than a light frost at 32 °F because the lower temperature can injure or kill plant tissue that survives the milder chill.

How to read the probabilities

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

  • Spring: "10% after March 20" 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 November 8" 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 Brenham, TXNumbered nearest stations: 1 — College Station, TX — 30 mi; 2 — Columbus, TX — 34 mi; 3 — Lexington, TX — 41 mi; 4 — Smithville, TX — 47 mi; 5 — Elgin, TX — 60 mi.TX25 mi · 40 km1. College Station, TX — 30 mi12. Columbus, TX — 34 mi23. Lexington, TX — 41 mi34. Smithville, TX — 47 mi45. Elgin, TX — 60 mi5
  1. College Station, TX 30 mi (48 km)
  2. Columbus, TX 34 mi (54 km)
  3. Lexington, TX 41 mi (65 km)
  4. Smithville, TX 47 mi (76 km)
  5. Elgin, TX 60 mi (96 km)

Sources

* Hardiness zone 9a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 30.1592, -96.3972.