WxDecoder

O12 Weather Grand Lake St Marys Seaplane Base

St Marys, OhioElevation 871 ftSeaplane base
OFF-FIELD REFERENCE
Nearest report: KAXV · 9 NM E · 11 min old
No ceiling, visibility 10 SM.
No on-field report, so no field flight category. Conditions at the field may differ.
OFF-FIELD REFERENCE · KAXV
WIND
Calm
no steady wind
VISIBILITY
10 SM
16.1 km
CEILING
None
no BKN/OVC layer
FORECAST & PILOT NOTES · SUPPLEMENTAL

Extended forecast and pilot notes

No aviation METAR is published for this airport. The nearest National Weather Service station reports wind calm, visibility 10 SM. Treat this as supplemental, not an aviation observation. Forecast suggests tonight partly cloudy, low near 49F, 1% chance of precipitation. Key risks: no significant hazards are highlighted right now, but always confirm against an official briefing.

DayConditionsTemp FWindGustsPrecipPilot note
Tonight Partly Cloudy 49 S 3 kt – 1%
Monday Mostly Sunny 72/50 W 3 kt – 2%
Tuesday Partly Sunny 70/53 E 5 kt – 0%
Wednesday Mostly Sunny 73/54 S 5 kt – 0%
Thursday Sunny 76/56 SW 10 kt – 3%
Friday Mostly Sunny 76/57 SW 5 kt – 4%
Saturday Partly Sunny then Slight Chance Light Rain 72/59 S 6 kt – 32%
Sunday Light Rain Likely 70 S 9 kt – 64%

Source: National Weather Service (office ILN). Forecast issued 0245Z.

Radar

Radar data: NOAA/NWS MRMS composite reflectivity. For situational awareness only, not a substitute for an official weather briefing.

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RUNWAYS & WIND
Crosswind calculator
No runway layout is available for O12. Enter a runway number or heading to estimate wind components.
RUNWAYS

Runway detail & declared distances

1 runway · longest 7,000 ft

09W/27W
Dimensions
7,000 x 4,000 ft
Surface
Water
RWY 09W
RWY 27W
Traffic patternRight

Runway data from the FAA NASR dataset (effective 2026-06-11). Verify with the current Chart Supplement and NOTAMs.

FIELD CONDITIONS

Field elevation

Field elevation
871 ft MSL

Density and pressure altitude need a current temperature and altimeter from the METAR.

DAYLIGHT & NIGHT

Sun & logging windows

Sunset
2243Z 6:43 PM
Sunrise
1200Z 8:00 AM
Loggable night
2311Z (7:11 PM local) → 1132Z (7:32 AM local)
end of evening to start of morning civil twilight
Position lights required
2243Z (6:43 PM local) → 1200Z (8:00 AM local)
sunset to sunrise (91.209)
Night passenger currency
2343Z (7:43 PM local) → 1100Z (7:00 AM local)
1 hr after sunset to 1 hr before sunrise (61.57(b))

FAA definitions, shown in Zulu with airport-local time. Verify for your operation.

AIRPORT INFORMATION

Facility & services

Grand Lake St Marys Seaplane Base is in St Marys, Ohio. Field elevation 871 ft MSL. Airport facts are drawn from OurAirports and the FAA NASR dataset.

OPERATIONS & CONTACT
OwnershipPublicly owned
UseOpen to the public
TypeSeaplane base
ManagerDAVID FALER, ASST PARK MGR
Manager phone419-394-3611
AttendedAPR-NOV ALL, 0800–1700
CHARTS & AIRSPACE
ICAO / IATAO12
SectionalDETROIT
Center (ARTCC)INDIANAPOLIS
Flight service (AFSS)DAYTON
RegionOhio
CountryUnited States
Coordinates40.5410, -84.4907
Distance from city5 NM NE
SERVICES & LIGHTING
Fuel100LL
Control towerNon-towered
CTAF122.900
FREQUENCIES

Communications

122.900
CTAF
CTAF

Not all tower/ground/approach frequencies are in our datasets. Verify with the FAA Chart Supplement.

AIRCRAFT ACTIVITY

Traffic patterns

Aircraft activity data is not available for this airport yet.

NEARBY AIRPORTS

Weather reference stations

O12 has no on-field report. Nearest reporting station: KAXV (9 NM E, VFR).

KAXV Neil Armstrong Airport
9 NM E
VFR
KAOH Lima Allen County Airport
23 NM NE
VFR
KDAY James M. Cox Dayton International Airport
40 NM S
VFR
KFWA Fort Wayne International Airport
41 NM NW
VFR
KMIE Delaware County Johnson Field
45 NM SW
VFR
KFDY Findlay Airport
47 NM NE
VFR
AIRPORT REMARKS

Operational remarks

›PRVDD 20:1 APCH; OIL WELL TO THE S MKD & LGTD; SEA LANES MKD & LGTD PER AC 150/5395-1.
›NO NGT OPS.
›NO PUB DOCKS; PPR FOR PVT DOCK TIE UP; CALL KOZY MARINA 419-394-8797.
›FOR CD CTC COLUMBUS APCH AT 614-338-8537.
›CELL 419-656-7060.
›ARPT CLSD NOV 15 TO APR 1 & MEMORIAL & LABOR DAY.
›100LL AVBL ON REQ, PPR, CTC KOZY MARINA 419-394-8797.
›ACFT OPRG AT GRAND LAKE ST MARYS SHOULD MNT TFC ON LAKEFIELD CTAF & NEIL ARMSTRONG CTAF.
OFFICIAL LINKS & SOURCES
↗Search NOTAMs (official FAA NOTAM Search)
↗Wikipedia
↗O12 on OurAirports
FREQUENTLY ASKED
Does O12 have a METAR?
No on-field METAR is issued for O12. This page uses the nearest reporting station as a reference.
Does O12 have a TAF?
No TAF is issued directly for O12. Use the nearest TAF-issuing field as a planning reference.
What is the field elevation at O12?
O12 sits at 871 ft MSL, which factors into the density-altitude estimate on this page.
Is this an official preflight weather briefing for O12?
No. wxdecoder.com is for education and situational awareness only. It is not an official weather briefing or a substitute for official sources, NOTAM review, and pilot judgment.
This app is for aviation weather education, training, and situational awareness only. It is not a substitute for an official weather briefing, approved flight-planning software, flight service, dispatch procedures, current FAA regulations, or pilot judgment. Always verify weather with official sources before flight.