U.S. Frost Dates by Weather Station

NOAA station USC00324646 · North Dakota

Frost Dates for Kenmare, ND

NOAA weather station Kenmare 1 WSW (USC00324646), North Dakota · elevation 1810 ft (552 m) · hardiness zone 4a*

  • Lower-risk planting dateafter May 28only 1 spring in 10 still has a frost later
  • Typical last frostMay 1550% chance of a frost after it
  • Typical first fall frostSeptember 2350% chance of a frost before it
  • Frost-free season129 daystypical year, 32°F
  • Hardiness zone4acalculated*

The year at a glance

Frost season at Kenmare, NDSpring: a frost after May 3 in 9 years out of 10, after May 15 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 10 in 1 year out of 10, before September 23 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 129 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 15First frost ~Sep 23Frost season at Kenmare, NDSpring: a frost after May 3 in 9 years out of 10, after May 15 in half of the years, after May 28 in 1 year out of 10. Fall: the first frost comes before September 10 in 1 year out of 10, before September 23 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 129 days.JFMAMJJASONDLast frost ~May 15First frost ~Sep 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.Today

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)May 28September 10
50% (typical)May 15September 23
90% (likely)May 3October 4
Frost-free season (32°F, 50% chance)
129 days
Hard frost (28°F), last in spring, 50% chance after
May 5
Hard frost (28°F), first in fall, 50% chance before
October 1

The last 15 years (2006–2020 normals)

Typical last frost May 15 (same as the 30-year normal), typical first fall frost September 26 (3 days later). Frost-free season 133 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 Kenmare: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 28, 20% May 23, 30% May 20, 40% May 17, 50% May 15, 60% May 12, 70% May 9, 80% May 6, 90% May 3. Observed last spring frost in recent years: 2021 May 29, 2022 May 20, 2023 May 1, 2024 May 4, 2025 May 16.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1May 28May 15May 32021: May 292022: May 202023: May 12024: May 42025: May 16Fall at Kenmare: chance of a frost before this dateFall, chance of a frost before the date: 10% September 10, 20% September 14, 30% September 17, 40% September 20, 50% September 23, 60% September 25, 70% September 27, 80% September 30, 90% October 4. Observed first fall frost in recent years: 2021 October 15, 2022 September 21, 2023 October 5, 2024 October 3, 2025 October 5.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 10Sep 23Oct 42021: October 152022: September 212023: October 52024: October 32025: October 5
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 29October 15
2022May 20September 21
2023May 1October 5
2024May 4October 3
2025May 16October 5
2026incomplete recordseason not over yet

What these dates mean

The cautious fall date in Kenmare for finishing the harvest is September 10, when there is only a 10 % chance a light frost has arrived.

The 50% dates—May 15 for spring and September 23 for fall—represent the points at which a light frost has an even chance of having occurred; they are not frost dates but help gauge the middle of the risk range. For a low-risk plan, tender crops are best set out after the cautious spring date of May 28 and harvested before the cautious fall date of September 10; the early spring date of May 3 and the late fall date of October 4 each carry a 90 % chance of frost and are considered gambles.

Hard-frost risk is marked by the 50% dates of May 5 in spring and October 1 in fall, and a hard frost at 28 °F can damage plants that survive a light frost at 32 °F, making it a more critical threshold.

How to read the probabilities

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

  • Spring: "10% after May 28" 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 10" 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 Kenmare, NDNumbered nearest stations: 1 — Minot (Airport), ND — 47 mi; 2 — near Minot, ND — 50 mi; 3 — Crosby, ND — 57 mi; 4 — Upham, ND — 63 mi; 5 — Keene, ND — 65 mi.ND25 mi · 40 km1. Minot (Airport), ND — 47 mi12. near Minot, ND — 50 mi23. Crosby, ND — 57 mi34. Upham, ND — 63 mi45. Keene, ND — 65 mi5
  1. Minot (Airport), ND 47 mi (76 km)
  2. near Minot, ND 50 mi (80 km)
  3. Crosby, ND 57 mi (92 km)
  4. Upham, ND 63 mi (101 km)
  5. Keene, ND 65 mi (105 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: 48.6692, -102.0975.