U.S. Frost Dates by Weather Station

NOAA station USC00418415 · Texas

Frost Dates for Smithville, TX

NOAA weather station Smithville (USC00418415), Texas · elevation 317 ft (97 m) · hardiness zone 9a*

  • Lower-risk planting dateafter April 11only 1 spring in 10 still has a frost later
  • Typical last frostMarch 1250% chance of a frost after it
  • Typical first fall frostNovember 1950% chance of a frost before it
  • Frost-free season251 daystypical year, 32°F
  • Hardiness zone9acalculated*

The year at a glance

Frost season at Smithville, TXSpring: a frost after February 18 in 9 years out of 10, after March 12 in half of the years, after April 11 in 1 year out of 10. Fall: the first frost comes before November 1 in 1 year out of 10, before November 19 in half of the years, before December 11 in 9 years out of 10. Typical frost-free season: 251 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Mar 12First frost ~Nov 19Frost season at Smithville, TXSpring: a frost after February 18 in 9 years out of 10, after March 12 in half of the years, after April 11 in 1 year out of 10. Fall: the first frost comes before November 1 in 1 year out of 10, before November 19 in half of the years, before December 11 in 9 years out of 10. Typical frost-free season: 251 days.JFMAMJJASONDLast frost ~Mar 12First frost ~Nov 19
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)April 11November 1
50% (typical)March 12November 19
90% (likely)February 18December 11
Frost-free season (32°F, 50% chance)
251 days
Hard frost (28°F), last in spring, 50% chance after
February 26
Hard frost (28°F), first in fall, 50% chance before
December 3

The last 15 years (2006–2020 normals)

Typical last frost March 13 (1 day later than the 30-year normal), typical first fall frost November 16 (3 days earlier). Frost-free season 249 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 Smithville: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 11, 20% April 5, 30% March 29, 40% March 19, 50% March 12, 60% March 8, 70% March 3, 80% February 27, 90% February 18.Spring: last frostChance of a frost after this date10%50%90%Mar 1Apr 1Apr 11Mar 12Feb 18Fall at Smithville: chance of a frost before this dateFall, chance of a frost before the date: 10% November 1, 20% November 6, 30% November 11, 40% November 15, 50% November 19, 60% November 24, 70% November 30, 80% December 4, 90% December 11.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Nov 1Nov 19Dec 11
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.

What these dates mean

April 11 marks the cautious spring light-frost date for Smithville, with only a 10 % chance that a 32 °F frost will occur later; this gives a gardener enough confidence to set out tender crops after that day. In the fall, November 1 is the cautious light-frost date, carrying a 10 % chance that a frost will have arrived earlier, allowing the gardener to finish harvesting tender crops by then.

The 50 % light-frost dates—March 12 for spring and November 19 for fall—represent the median point where frost is equally likely to occur later (spring) or earlier (fall). The hard-frost median dates are February 26 in spring and December 3 in fall; these are the points at which a 28 °F frost has a 50 % chance of having happened.

A hard frost at 28 °F can damage plants that survive a light frost at 32 °F, so it represents a greater risk to tender crops.

How to read the probabilities

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

  • Spring: "10% after April 11" 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 1" 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 Smithville, TXNumbered nearest stations: 1 — Elgin, TX — 27 mi; 2 — Lexington, TX — 29 mi; 3 — Luling, TX — 37 mi; 4 — Columbus, TX — 41 mi; 5 — Brenham, TX — 47 mi.TX25 mi · 40 km1. Elgin, TX — 27 mi12. Lexington, TX — 29 mi23. Luling, TX — 37 mi34. Columbus, TX — 41 mi45. Brenham, TX — 47 mi5
  1. Elgin, TX 27 mi (44 km)
  2. Lexington, TX 29 mi (46 km)
  3. Luling, TX 37 mi (60 km)
  4. Columbus, TX 41 mi (67 km)
  5. Brenham, TX 47 mi (76 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: 30.0092, -97.1644.