U.S. Frost Dates by Weather Station

NOAA station USC00187806 · Maryland

Frost Dates for Royal Oak, MD

NOAA weather station Royal Oak 2 SSW (USC00187806), Maryland · elevation 10 ft (3 m) · hardiness zone 8a*

  • Lower-risk planting dateafter April 15only 1 spring in 10 still has a frost later
  • Typical last frostApril 150% chance of a frost after it
  • Typical first fall frostNovember 750% chance of a frost before it
  • Frost-free season220 daystypical year, 32°F
  • Hardiness zone8acalculated*

The year at a glance

Frost season at Royal Oak, MDSpring: a frost after March 18 in 9 years out of 10, after April 1 in half of the years, after April 15 in 1 year out of 10. Fall: the first frost comes before October 24 in 1 year out of 10, before November 7 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 220 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 1First frost ~Nov 7Frost season at Royal Oak, MDSpring: a frost after March 18 in 9 years out of 10, after April 1 in half of the years, after April 15 in 1 year out of 10. Fall: the first frost comes before October 24 in 1 year out of 10, before November 7 in half of the years, before November 23 in 9 years out of 10. Typical frost-free season: 220 days.JFMAMJJASONDLast frost ~Apr 1First frost ~Nov 7
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)April 15October 24
50% (typical)April 1November 7
90% (likely)March 18November 23
Frost-free season (32°F, 50% chance)
220 days
Hard frost (28°F), last in spring, 50% chance after
March 20
Hard frost (28°F), first in fall, 50% chance before
November 20

The last 15 years (2006–2020 normals)

Typical last frost April 2 (1 day later than the 30-year normal), typical first fall frost November 10 (3 days later). Frost-free season 222 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 Royal Oak: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 15, 20% April 10, 30% April 7, 40% April 4, 50% April 1, 60% March 30, 70% March 27, 80% March 23, 90% March 18. Observed last spring frost in recent years: 2021 April 2, 2022 April 11, 2023 March 21, 2024 March 25, 2025 March 27, 2026 April 9.Spring: last frostChance of a frost after this date10%50%90%Apr 1Apr 15Apr 1Mar 182021: April 22022: April 112023: March 212024: March 252025: March 272026: April 9Fall at Royal Oak: chance of a frost before this dateFall, chance of a frost before the date: 10% October 24, 20% October 30, 30% November 2, 40% November 5, 50% November 7, 60% November 10, 70% November 13, 80% November 17, 90% November 23. Observed first fall frost in recent years: 2021 November 15, 2022 November 15, 2023 November 13, 2024 November 30, 2025 November 18.Fall: first frostChance of a frost before this date10%50%90%Nov 1Dec 1Oct 24Nov 7Nov 232021: November 152022: November 152023: November 132024: November 302025: November 18
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 2November 15
2022April 11November 15
2023March 21November 13
2024March 25November 30
2025March 27November 18
2026April 9season not over yet

What these dates mean

Royal Oak enjoys 220 days between the 32°F 50% dates, a span that fits the growing season for most tender crops.

For a gardener, the 50% dates—April 1 in spring and November 7 in fall—are the points when a light frost is equally likely, while the hard-frost 50% dates—March 20 and November 20—mark an even chance of a 28 °F event. The cautious spring date for tender crops is April 15, which carries a 10 % chance of a later frost, and the cautious fall date is October 24, which carries a 10 % chance of an earlier frost. Planting as early as March 18 or as late as November 23 carries a 90 % chance of frost and is therefore risky.

A hard frost at 28 °F can harm plants that survive a light frost at 32 °F, making it the 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 April 15" 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 24" 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 Royal Oak, MDNumbered nearest stations: 1 — near Lexington Park, MD — 31 mi; 2 — Mechanicsville, MD — 33 mi; 3 — near Baltimore, MD — 41 mi; 4 — near Bladensburg, MD — 44 mi; 5 — near Salisbury, MD — 45 mi.MDDEVANJ25 mi · 40 km1. near Lexington Park, MD — 31 mi12. Mechanicsville, MD — 33 mi23. near Baltimore, MD — 41 mi34. near Bladensburg, MD — 44 mi45. near Salisbury, MD — 45 mi5
  1. near Lexington Park, MD 31 mi (50 km)
  2. Mechanicsville, MD 33 mi (53 km)
  3. near Baltimore, MD 41 mi (66 km)
  4. near Bladensburg, MD 44 mi (71 km)
  5. near Salisbury, MD 45 mi (72 km)

Sources

* Hardiness zone 8a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 38.7153, -76.1908.