83°
Mostly Cloudy
13%
75
Washington County, MD · Lake
Greenbrier State Park
21843 National Pike, Boonsboro, MD 21713
42-acre man-made freshwater lake with a white-sand swim beach on South Mountain northeast of Boonsboro. Popular with DC/Baltimore day-trippers, so MD DNR now requires advance reservations on weekends/holidays Memorial Day–Labor Day.
Today's Conditions
Ideal for photography.
83°F air
Full NWS forecast for Today
Mostly cloudy, with a high near 83. East wind 6 to 9 mph.
Tonight
Partly cloudy, with a low around 64. Southeast wind 3 to 9 mph.
Weather
- 83°F air — ideal beach weather
- Cloud cover — overcast reduces uv exposure but the vibe too
74 /100
great
69 Sunbathe
78 Walk
88 Fish
85 Photo
Best for photography today
Atmosphere
Air Temp
83°F
Mostly Cloudy
Wind
6 to 9 mph
E
Rain
13%
Today
UV Peak
7 High
High 11 AM–01 PM · burn in ~29m
Burn-free before 09 AM & after 05 PM
Tomorrow
83°F
Sunny
Water
Water Temp
—
Next High Tide
5:14 PM
1.2 ft · in 2.0h
Water Quality
Clean
6 MPN/100mL · E. coli
USGS · sampled 10mo ago
Sun & Moon
Sunrise
5:53 AM
Sunset
8:38 PM
Moon · 5%
Waning Crescent
Spring tides — bigger range
7-Day Beach Day Forecast
83°
Sunny
0%
85
88°
Sunny
0%
83
96°
Sunny
1%
66
92°
Mostly Sunny
4%
74
90°
Mostly Sunny
12%
76
89°
Mostly Sunny then Chance Showers And Thunderstorms
30%
42
What to Bring Today
- recommended SPF 30 sunscreen UV index 7 — high
- recommended Umbrella or shade warm day, light wind
Always remember water bottle, trash bag (leave no trace).
Best Fishing Times Today
Solunar theory: fish activity peaks at moon transits (major) and moonrise/moonset (minor). All times local.
Major
10:00 PM - 12:00 AM
Minor
3:00 AM - 4:00 AM
Major
10:30 AM - 12:30 PM
Minor
7:10 PM - 8:10 PM
Beach Info
Parking
State park lot.
Dogs
Dogs permitted on leash in designated areas; not on swim beach.
Entry Fee
$3/person MD resident, $5/person out-of-state (May/Sep weekends); higher in-season. Advance day-use reservation required weekends & holidays Memorial Day–Labor Day.
Address
21843 National Pike, Boonsboro, MD 21713
Amenities
Frequently Asked
Is it safe to swim at Greenbrier State Park today?
Greenbrier State Park shows a live water-quality reading (bacteria levels) and today's swim-safety score at the top of this page, refreshed on every update. Seasonal lifeguards patrol the swim area in summer — follow their flags. Always review the current advisories, surf, and rip-current notes before getting in the water.
Is Greenbrier State Park dog-friendly?
Dogs permitted on leash in designated areas; not on swim beach.
Is there an entry fee at Greenbrier State Park?
$3/person MD resident, $5/person out-of-state (May/Sep weekends); higher in-season. Advance day-use reservation required weekends & holidays Memorial Day–Labor Day.
Are there lifeguards at Greenbrier State Park?
Yes. Seasonal lifeguards patrol Greenbrier State Park during the summer swim season (typically Memorial Day through Labor Day). Outside that window, swim at your own risk.
What amenities are at Greenbrier State Park?
Amenities at Greenbrier State Park include lifeguards, beach, camping, boat launch, boat rentals, fishing, trails, restrooms.
When is the water warmest at Greenbrier State Park?
Inland lakes peak in July and August at 75-80°F and hold warmth longer than tidal beaches. Swimming comfortable from mid-June through September.
Where is Greenbrier State Park located?
Greenbrier State Park is in Washington County, MD, at 21843 National Pike, Boonsboro, MD 21713.
Nearby Beaches
Updated · Data from NOAA, NWS