U.S. Frost Dates by Weather Station

NOAA station USC00323287 · North Dakota

Frost Dates for Fullerton, ND

NOAA weather station Fullerton 1 ESE (USC00323287), North Dakota · elevation 1435 ft (437 m) · hardiness zone 4a*

  • Lower-risk planting dateafter May 23only 1 spring in 10 still has a frost later
  • Typical last frostMay 950% chance of a frost after it
  • Typical first fall frostSeptember 2850% chance of a frost before it
  • Frost-free season141 daystypical year, 32°F
  • Hardiness zone4acalculated*

The year at a glance

Frost season at Fullerton, NDSpring: a frost after April 27 in 9 years out of 10, after May 9 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 17 in 1 year out of 10, before September 28 in half of the years, before October 11 in 9 years out of 10. Typical frost-free season: 141 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 9First frost ~Sep 28Frost season at Fullerton, NDSpring: a frost after April 27 in 9 years out of 10, after May 9 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 17 in 1 year out of 10, before September 28 in half of the years, before October 11 in 9 years out of 10. Typical frost-free season: 141 days.JFMAMJJASONDLast frost ~May 9First frost ~Sep 28
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.Today

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 23September 17
50% (typical)May 9September 28
90% (likely)April 27October 11
Frost-free season (32°F, 50% chance)
141 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 5

The last 15 years (2006–2020 normals)

Typical last frost May 8 (1 day earlier than the 30-year normal), typical first fall frost October 1 (3 days later). Frost-free season 144 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 Fullerton: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 23, 20% May 18, 30% May 15, 40% May 12, 50% May 9, 60% May 6, 70% May 3, 80% May 1, 90% April 27. Observed last spring frost in recent years: 2021 May 11, 2022 May 2.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 23May 9Apr 272021: May 112022: May 2Fall at Fullerton: chance of a frost before this dateFall, chance of a frost before the date: 10% September 17, 20% September 21, 30% September 23, 40% September 26, 50% September 28, 60% October 1, 70% October 3, 80% October 6, 90% October 11. Observed first fall frost in recent years: 2021 October 21, 2022 September 28, 2023 October 6.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 17Sep 28Oct 112021: October 212022: September 282023: October 6
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 11October 21
2022May 2September 28
2023incomplete recordOctober 6
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

Setting out tender crops on April 27 in Fullerton carries a 90% chance of a light frost later that season, making it a gamble. The cautious spring date for tender crops is May 23, when only a 10% chance of a light frost later remains. The 50% date of May 9 marks the point where a light frost is equally likely to occur later or not.

In the fall, September 17 is the cautious date, offering only a 10% chance that a light frost has arrived earlier; waiting until October 11 raises that risk to 90%, a gamble for late-season tender crops. The 50% date of September 28 indicates an even odds that a light frost will have arrived earlier. The hard-frost median dates, April 30 in spring and October 5 in fall, show when a 28°F frost becomes as likely as not, and such a hard frost can damage plants that would survive a 32°F 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 23" 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 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 Fullerton, NDNumbered nearest stations: 1 — Columbia, SD — 30 mi; 2 — Forman, ND — 39 mi; 3 — Britton, SD — 40 mi; 4 — Ashley, ND — 47 mi; 5 — Aberdeen, SD — 49 mi.SD25 mi · 40 km1. Columbia, SD — 30 mi12. Forman, ND — 39 mi23. Britton, SD — 40 mi34. Ashley, ND — 47 mi45. Aberdeen, SD — 49 mi5
  1. Columbia, SD 30 mi (49 km)
  2. Forman, ND 39 mi (64 km)
  3. Britton, SD 40 mi (65 km)
  4. Ashley, ND 47 mi (76 km)
  5. Aberdeen, SD 49 mi (78 km)

Sources

* Hardiness zone 4a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 46.1583, -98.3989.