U.S. Frost Dates by Weather Station

NOAA station USW00093721 · Maryland

Frost Dates near Baltimore, MD

NOAA weather station Baltimore Wash International Airport (USW00093721), Maryland · elevation 156 ft (48 m) · hardiness zone 7b*

Baltimore is the nearest town to the station (9.4 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 April 25only 1 spring in 10 still has a frost later
  • Typical last frostApril 1050% chance of a frost after it
  • Typical first fall frostOctober 3150% chance of a frost before it
  • Frost-free season204 daystypical year, 32°F
  • Hardiness zone7bcalculated*

The year at a glance

Frost season near Baltimore, MDSpring: a frost after March 27 in 9 years out of 10, after April 10 in half of the years, after April 25 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 31 in half of the years, before November 12 in 9 years out of 10. Typical frost-free season: 204 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 10First frost ~Oct 31Frost season near Baltimore, MDSpring: a frost after March 27 in 9 years out of 10, after April 10 in half of the years, after April 25 in 1 year out of 10. Fall: the first frost comes before October 17 in 1 year out of 10, before October 31 in half of the years, before November 12 in 9 years out of 10. Typical frost-free season: 204 days.JFMAMJJASONDLast frost ~Apr 10First frost ~Oct 31
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 25October 17
50% (typical)April 10October 31
90% (likely)March 27November 12
Frost-free season (32°F, 50% chance)
204 days
Hard frost (28°F), last in spring, 50% chance after
March 28
Hard frost (28°F), first in fall, 50% chance before
November 10

The last 15 years (2006–2020 normals)

Typical last frost April 8 (2 days earlier than the 30-year normal), typical first fall frost November 2 (2 days later). Frost-free season 208 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 Baltimore: chance of a frost after this dateSpring, chance of a frost after the date: 10% April 25, 20% April 19, 30% April 16, 40% April 13, 50% April 10, 60% April 7, 70% April 3, 80% March 31, 90% March 27. Observed last spring frost in recent years: 2021 April 3, 2022 April 29, 2023 March 21, 2024 March 26, 2025 April 9, 2026 April 21.Spring: last frostChance of a frost after this date10%50%90%Apr 1May 1Apr 25Apr 10Mar 272021: April 32022: April 292023: March 212024: March 262025: April 92026: April 21Fall near Baltimore: chance of a frost before this dateFall, chance of a frost before the date: 10% October 17, 20% October 22, 30% October 26, 40% October 29, 50% October 31, 60% November 2, 70% November 5, 80% November 7, 90% November 12. Observed first fall frost in recent years: 2021 November 4, 2022 November 14, 2023 November 2, 2024 October 17, 2025 November 7.Fall: first frostChance of a frost before this date10%50%90%Nov 1Oct 17Oct 31Nov 122021: November 42022: November 142023: November 22024: October 172025: November 7
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 3November 4
2022April 29November 14
2023March 21November 2
2024March 26October 17
2025April 9November 7
2026April 21season not over yet

What these dates mean

April 25 is the cautious spring date for the Baltimore area, and it allows a gardener to set out tender crops with only a 10 % chance that a light frost will occur later. Planting after this date keeps the risk low, while the earlier date of March 27 carries a 90 % chance of frost and is a gamble.

April 10 is the 50 % date, meaning there is a 50 % chance of a frost later than this date, and October 31 is the 50 % fall date, meaning there is a 50 % chance of a frost earlier than this date. The cautious fall date of October 17 gives a 10 % chance that a light frost has already arrived, so finishing tender-crop harvest before then keeps risk low.

Hard frost at 28 °F (median dates March 28 in spring and November 10) can injure plants that survive a light 32 °F frost, making its timing more critical.

How to read the probabilities

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

  • Spring: "10% after April 25" 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 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 Baltimore, MDNumbered nearest stations: 1 — Beltsville, MD — 16 mi; 2 — near Bladensburg, MD — 23 mi; 3 — near Arlington, VA — 29 mi; 4 — Millers, MD — 39 mi; 5 — Royal Oak, MD — 41 mi.PAVADENJWV25 mi · 40 km1. Beltsville, MD — 16 mi12. near Bladensburg, MD — 23 mi23. near Arlington, VA — 29 mi34. Millers, MD — 39 mi45. Royal Oak, MD — 41 mi5
  1. Beltsville, MD 16 mi (26 km)
  2. near Bladensburg, MD 23 mi (38 km)
  3. near Arlington, VA 29 mi (47 km)
  4. Millers, MD 39 mi (62 km)
  5. Royal Oak, MD 41 mi (66 km)

Sources

* Hardiness zone 7b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 39.1667, -76.6833.