U.S. Frost Dates by Weather Station

NOAA station USC00230789 · Missouri

Frost Dates for Bolivar, MO

NOAA weather station Bolivar 1 NE (USC00230789), Missouri · elevation 987 ft (301 m) · hardiness zone 6b*

  • Lower-risk planting dateafter May 2only 1 spring in 10 still has a frost later
  • Typical last frostApril 1450% chance of a frost after it
  • Typical first fall frostOctober 2350% chance of a frost before it
  • Frost-free season188 daystypical year, 32°F
  • Hardiness zone6bcalculated*

The year at a glance

Frost season at Bolivar, MOSpring: a frost after March 29 in 9 years out of 10, after April 14 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 8 in 1 year out of 10, before October 23 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 188 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 14First frost ~Oct 23Frost season at Bolivar, MOSpring: a frost after March 29 in 9 years out of 10, after April 14 in half of the years, after May 2 in 1 year out of 10. Fall: the first frost comes before October 8 in 1 year out of 10, before October 23 in half of the years, before November 4 in 9 years out of 10. Typical frost-free season: 188 days.JFMAMJJASONDLast frost ~Apr 14First frost ~Oct 23
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 30 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 2October 8
50% (typical)April 14October 23
90% (likely)March 29November 4
Frost-free season (32°F, 50% chance)
188 days
Hard frost (28°F), last in spring, 50% chance after
April 1
Hard frost (28°F), first in fall, 50% chance before
November 1

The last 15 years (2006–2020 normals)

Typical last frost April 11 (3 days earlier than the 30-year normal), typical first fall frost October 23. Frost-free season 195 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 Bolivar: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 2, 20% April 26, 30% April 21, 40% April 18, 50% April 14, 60% April 11, 70% April 7, 80% April 2, 90% March 29. Observed last spring frost in recent years: 2021 April 23, 2022 April 19, 2023 April 24, 2024 April 22, 2025 April 9, 2026 March 28.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1May 2Apr 14Mar 292021: April 232022: April 192023: April 242024: April 222025: April 92026: March 28Fall at Bolivar: chance of a frost before this dateFall, chance of a frost before the date: 10% October 8, 20% October 14, 30% October 17, 40% October 20, 50% October 23, 60% October 25, 70% October 28, 80% November 1, 90% November 4. Observed first fall frost in recent years: 2021 November 4, 2022 October 18, 2023 October 30, 2024 October 16, 2025 November 2.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Oct 8Oct 23Nov 42021: November 42022: October 182023: October 302024: October 162025: November 2
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 23November 4
2022April 19October 18
2023April 24October 30
2024April 22October 16
2025April 9November 2
2026March 28season not over yet

What these dates mean

Setting out tender crops on March 29 in Bolivar is a gamble, because there is a 90% chance that a light frost will occur later that spring. The more cautious approach waits until May 2, when only a 10% chance of a later frost remains.

The 50% date for light frost in spring is April 14, giving a garden a 50% chance of a frost later than that day; in fall the 50% date is October 23, with a 50% chance of a frost earlier than that day. For a conservative schedule, tender crops should be finished by October 8, the date with only a 10% chance that a frost has already arrived.

Hard frost, recorded at 28 °F, is more damaging than a light 32 °F frost, so the median hard-frost dates of April 1 and November 1 are useful reference points for crops that cannot survive temperatures below 28 °F.

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 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 Bolivar, MONumbered nearest stations: 1 — near Stockton, MO — 22 mi; 2 — Springfield, MO — 26 mi; 3 — Marshfield, MO — 30 mi; 4 — Lebanon, MO — 38 mi; 5 — Billings, MO — 40 mi.MO25 mi · 40 km1. near Stockton, MO — 22 mi12. Springfield, MO — 26 mi23. Marshfield, MO — 30 mi34. Lebanon, MO — 38 mi45. Billings, MO — 40 mi5
  1. near Stockton, MO 22 mi (35 km)
  2. Springfield, MO 26 mi (42 km)
  3. Marshfield, MO 30 mi (49 km)
  4. Lebanon, MO 38 mi (62 km)
  5. Billings, MO 40 mi (65 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: 37.6164, -93.3914.