U.S. Frost Dates by Weather Station

NOAA station USW00014914 · North Dakota

Frost Dates near Fargo, ND

NOAA weather station Fargo Hector International Airport (USW00014914), North Dakota · elevation 900 ft (274 m) · hardiness zone 4a*

Fargo is the nearest town to the station (3.5 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 May 23only 1 spring in 10 still has a frost later
  • Typical last frostMay 1050% chance of a frost after it
  • Typical first fall frostSeptember 3050% chance of a frost before it
  • Frost-free season143 daystypical year, 32°F
  • Hardiness zone4acalculated*

The year at a glance

Frost season near Fargo, NDSpring: a frost after April 27 in 9 years out of 10, after May 10 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before September 30 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 143 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 10First frost ~Sep 30Frost season near Fargo, NDSpring: a frost after April 27 in 9 years out of 10, after May 10 in half of the years, after May 23 in 1 year out of 10. Fall: the first frost comes before September 18 in 1 year out of 10, before September 30 in half of the years, before October 15 in 9 years out of 10. Typical frost-free season: 143 days.JFMAMJJASONDLast frost ~May 10First frost ~Sep 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 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)May 23September 18
50% (typical)May 10September 30
90% (likely)April 27October 15
Frost-free season (32°F, 50% chance)
143 days
Hard frost (28°F), last in spring, 50% chance after
April 30
Hard frost (28°F), first in fall, 50% chance before
October 10

The last 15 years (2006–2020 normals)

Typical last frost May 10 (same as the 30-year normal), typical first fall frost October 3 (3 days later). Frost-free season 145 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 Fargo: 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 10, 60% May 7, 70% May 4, 80% May 1, 90% April 27. Observed last spring frost in recent years: 2021 May 28, 2022 May 22, 2023 April 29, 2024 April 24, 2025 April 29, 2026 May 20.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 23May 10Apr 272021: May 282022: May 222023: April 292024: April 242025: April 292026: May 20Fall near Fargo: chance of a frost before this dateFall, chance of a frost before the date: 10% September 18, 20% September 22, 30% September 25, 40% September 28, 50% September 30, 60% October 3, 70% October 5, 80% October 9, 90% October 15. Observed first fall frost in recent years: 2021 October 20, 2022 October 6, 2023 October 10, 2024 October 14, 2025 October 21.Fall: first frostChance of a frost before this date10%50%90%Oct 1Sep 18Sep 30Oct 152021: October 202022: October 62023: October 102024: October 142025: October 21
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 28October 20
2022May 22October 6
2023April 29October 10
2024April 24October 14
2025April 29October 21
2026May 20season not over yet

What these dates mean

In the Fargo area there are 143 days between the two 32°F 50% dates, May 10 and September 30, and that span defines the period when light frosts are equally likely to have occurred or not. Gardeners can use that interval to plan planting, harvesting, and other activities, knowing that a light frost at 32°F is the threshold used for the probability charts.

May 23 is the cautious date for setting out tender crops in spring, because only a 10% chance of a light frost remains after it; planting on April 27 would be a gamble with a 90% chance of frost later. In fall, September 18 serves as the cautious date to finish harvesting tender crops, as there is only a 10% chance a light frost has arrived before then, while waiting until October 15 would be a gamble with a 90% chance of earlier frost. Hard frost dates—April 30 in spring and October 10 in fall—matter more because temperatures of 28°F can injure plants that survive the milder 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 18" 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 Fargo, NDNumbered nearest stations: 1 — Georgetown, MN — 11 mi; 2 — near Casselton, ND — 20 mi; 3 — Rothsay, MN — 39 mi; 4 — McLeod, ND — 42 mi; 5 — near Crookston, MN — 62 mi.MNND25 mi · 40 km1. Georgetown, MN — 11 mi12. near Casselton, ND — 20 mi23. Rothsay, MN — 39 mi34. McLeod, ND — 42 mi45. near Crookston, MN — 62 mi5
  1. Georgetown, MN 11 mi (17 km)
  2. near Casselton, ND 20 mi (32 km)
  3. Rothsay, MN 39 mi (64 km)
  4. McLeod, ND 42 mi (68 km)
  5. near Crookston, MN 62 mi (100 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: 46.9253, -96.8111.