U.S. Frost Dates by Weather Station

NOAA station USC00418236 · Texas

Frost Dates near Shamrock, TX

NOAA weather station Shamrock #2 (USC00418236), Texas · elevation 2360 ft (719 m) · hardiness zone 7a*

Shamrock is the nearest town to the station (0.1 mi away) in GeoNames (CC BY 4.0). The dates below are measured at the station, not in the town itself.

  • Lower-risk planting dateafter April 26only 1 spring in 10 still has a frost later
  • Typical last frostApril 950% chance of a frost after it
  • Typical first fall frostOctober 3050% chance of a frost before it
  • Frost-free season202 daystypical year, 32°F
  • Hardiness zone7acalculated*

The year at a glance

Frost season near Shamrock, TXSpring: a frost after March 26 in 9 years out of 10, after April 9 in half of the years, after April 26 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 30 in half of the years, before November 11 in 9 years out of 10. Typical frost-free season: 202 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 9First frost ~Oct 30Frost season near Shamrock, TXSpring: a frost after March 26 in 9 years out of 10, after April 9 in half of the years, after April 26 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 30 in half of the years, before November 11 in 9 years out of 10. Typical frost-free season: 202 days.JFMAMJJASONDLast frost ~Apr 9First frost ~Oct 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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)April 26October 17
50% (typical)April 9October 30
90% (likely)March 26November 11
Frost-free season (32°F, 50% chance)
202 days
Hard frost (28°F), last in spring, 50% chance after
March 31
Hard frost (28°F), first in fall, 50% chance before
November 6

The last 15 years (2006–2020 normals)

Typical last frost April 10 (1 day later than the 30-year normal), typical first fall frost November 1 (2 days later). Frost-free season 202 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 near Shamrock: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 26, 20% April 20, 30% April 16, 40% April 13, 50% April 9, 60% April 6, 70% April 4, 80% April 1, 90% March 26.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 26Apr 9Mar 26Fall near Shamrock: chance of a frost before this dateFall, chance of a frost before the date: 10% October 17, 20% October 21, 30% October 25, 40% October 27, 50% October 30, 60% November 1, 70% November 4, 80% November 7, 90% November 11.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 17Oct 30Nov 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 26 is the cautious spring date in the Shamrock area; with only a 10 % chance of a light frost later, it lets a gardener set out tender crops with minimal risk. The 50 % date is April 9, meaning there is an even chance of a light frost occurring after that point.

October 17 is the cautious fall date for finishing the harvest of tender crops, as only a 10 % chance of a light frost has arrived by then. The 50 % date is October 30, indicating a 50 % chance of a light frost occurring before that day. These two median dates are 202 days apart, based on 26 years of observations, and mark the span between equal odds of a light frost in spring and in fall.

Hard-frost dates are March 31 in spring and November 6 in fall; hard frost at 28 °F can cause more severe damage than a light frost at 32 °F, because it reaches temperatures where even dormant plants can suffer tissue loss, making it a higher concern for growers.

How to read the probabilities

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

  • Spring: "10% after April 26" 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 17" 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 Shamrock, TXNumbered nearest stations: 1 — Wellington, TX — 26 mi; 2 — Memphis, TX — 37 mi; 3 — near Pampa, TX — 47 mi; 4 — Childress, TX — 54 mi; 5 — Turkey, TX — 67 mi.TXOK25 mi · 40 km1. Wellington, TX — 26 mi12. Memphis, TX — 37 mi23. near Pampa, TX — 47 mi34. Childress, TX — 54 mi45. Turkey, TX — 67 mi5
  1. Wellington, TX 26 mi (42 km)
  2. Memphis, TX 37 mi (60 km)
  3. near Pampa, TX 47 mi (76 km)
  4. Childress, TX 54 mi (88 km)
  5. Turkey, TX 67 mi (109 km)

Sources

* Hardiness zone 7a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 35.215, -100.2503.