Frost dates for Baltimore Wash Intl Ap, Maryland
Half of years have their last spring frost by April 10 — but 1 year in 10 still frosts after April 25.
Every other site gives you one date. A frost date is not a date: it is a percentile from 30 years of records at a nearby weather station, and planting to the median means losing the crop in half of years. Both numbers are below, so you can choose the risk yourself.
The odds
Last spring frost
- Frost this late in 1 year in 10
- April 25
- 1 year in 5
- April 19
- 3 years in 10
- April 16
- 2 years in 5
- April 13
- Half of years (the median)
- April 10
First fall freeze
- Freeze this early in 1 year in 10
- October 17
- 1 year in 5
- October 22
- 3 years in 10
- October 26
- 2 years in 5
- October 29
- Half of years (the median)
- October 31
- Growing season
- about 204 days
- Hardiness zones nearby
- 7a, 7b, 8a
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, station Baltimore Wash Intl Ap (USW00093721), at 39.17, -76.68. These are that station's own records, unshifted. The further your garden is from it, the less exactly they describe your ground — the planner resolves the nearest station to your own ZIP and lowers its confidence with distance, rather than presenting one number as if it were measured in your yard.
Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a hundred metres away does not. No table can know that about your garden. Your own logged frosts eventually can.
ZIP codes nearest this station
20701, 20705, 20707, 20708, 20723, 20724, 20755, 20759, 20763, 20777, 20794, 20866, 20868, 20904, 21012, 21032, 21042, 21043, 21044, 21045, 21046, 21052, 21054, 21056, 21057, 21060, 21061, 21075, 21076, 21077, 21090, 21093, 21104, 21108, 21113, 21114, 21117, 21122, 21128, 21133, 21144, 21146, 21153, 21162, 21163, 21201, 21202, 21204, 21205, 21206, 21207, 21208, 21209, 21210, 21211, 21212, 21213, 21214, 21215, 21216, 21217, 21218, 21219, 21220, 21221, 21222, 21223, 21224, 21225, 21226, 21227, 21228, 21229, 21230, 21231, 21234, 21236, 21237, 21239, 21240, 21244, 21250, 21251, 21252, 21286, 21401, 21402, 21405, 21409.
What can I plant here, and when? →
Nearby stations
The nearest stations, and how their last-frost dates compare — the frost gradient across your area, which no single station shows.
- Upper Marlboro 3 Nnw, MD — last frost by April 9
- Damascus 3 Ssw, MD — last frost by April 14
- Vienna, VA — last frost by April 14
- Millers 4 Ne, MD — last frost by April 19
- Royal Oak 2 Ssw Hcn, MD — last frost by April 1
- Conowingo Dam, MD — last frost by April 3
Other stations in Maryland.
- Mechanicsville 5 Ne, MD — last frost by April 17
- Patuxent River Nas, MD — last frost by March 29
- Hagerstown Washington Co Ap, MD — last frost by April 7
- Salisbury Hcn, MD — last frost by April 3
- Cumberland 2 Hcn, MD — last frost by April 15