Frost dates for Royal Oak 2 Ssw Hcn, Maryland
Half of years have their last spring frost by April 1 — but 1 year in 10 still frosts after April 15.
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 15
- 1 year in 5
- April 10
- 3 years in 10
- April 7
- 2 years in 5
- April 4
- Half of years (the median)
- April 1
First fall freeze
- Freeze this early in 1 year in 10
- October 24
- 1 year in 5
- October 30
- 3 years in 10
- November 2
- 2 years in 5
- November 5
- Half of years (the median)
- November 7
- Growing season
- about 220 days
- Hardiness zones nearby
- 7b, 8a
Where these numbers come from
NOAA NCEI 1991–2020 Climate Normals, station Royal Oak 2 Ssw Hcn (USC00187806), at 38.72, -76.19. 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
21601, 21612, 21613, 21619, 21624, 21625, 21631, 21638, 21641, 21643, 21647, 21648, 21652, 21653, 21654, 21655, 21658, 21662, 21663, 21664, 21665, 21666, 21671, 21673, 21676, 21677, 21679, 21835.
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.
- Patuxent River Nas, MD — last frost by March 29
- Upper Marlboro 3 Nnw, MD — last frost by April 9
- Mechanicsville 5 Ne, MD — last frost by April 17
- Salisbury Hcn, MD — last frost by April 3
- Baltimore Wash Intl Ap, MD — last frost by April 10
- Vienna, VA — last frost by April 14
Other stations in Maryland.
- Conowingo Dam, MD — last frost by April 3
- Damascus 3 Ssw, MD — last frost by April 14
- Millers 4 Ne, MD — last frost by April 19
- Hagerstown Washington Co Ap, MD — last frost by April 7
- Cumberland 2 Hcn, MD — last frost by April 15