GLRC Observatory (GRCM4) — Live Marine Conditions & Buoy Data
NOAA station GRCM4, GLRC Observatory, reports real-time marine conditions from 47.121°N, 88.545°W in Lake Superior. Readings refresh roughly every 10 minutes, and Big Buoy adds a solunar table and a multi-day weather outlook for the area.
Lake Superior Marine Conditions — GLRC Observatory is one of several stations in Lake Superior. See live buoy data and solunar for the whole area.
Current conditions at GLRC Observatory
As of August 21, 2026 at 18:40 UTC, GLRC Observatory (GRCM4) is reporting air temperature 69°F and wind from the SW at 9 mph.
- Air temperature
- 69°F
- Wind
- SW 9 mph
Observed August 21, 2026 at 18:40 UTC from NOAA NDBC station GRCM4. Readings update about every 10 minutes.
What NOAA buoy GRCM4 measures
As a NOAA meteorological station, GRCM4 reports wind speed, gusts and direction, barometric pressure, air and water temperature, and — where wave sensors are fitted — significant wave height, swell period, and wave direction.
What to watch in Lake Superior
Lake Superior is the coldest, deepest, and largest of the Great Lakes, with enough open water and fetch to build true offshore seas. Water stays cold most of the year and storms move through fast, so a sustained blow can raise steep, short-period waves with little warning — read wind, fetch, and sea state together before heading out.
Frequently asked questions
- Where is NOAA buoy GRCM4 located?
- GLRC Observatory (GRCM4) reports from 47.121°N, 88.545°W in Lake Superior.
- How often is NOAA buoy GRCM4 updated?
- Station GRCM4 typically reports new observations about every 10 minutes. Big Buoy refreshes continuously so you always see the latest readings, alongside a solunar table for the area.
- What does NOAA buoy GRCM4 measure?
- Big Buoy shows wind, barometric pressure, air and water temperature, and wave height and period where available for GLRC Observatory, plus solunar peak windows and a multi-day weather outlook.
- Is Big Buoy free to use?
- Yes. Live data for GLRC Observatory and every other NOAA buoy is free with no account required. Big Buoy Pro adds the Wind Tab, the Depth Chart, satellite overlays (sea surface temp, chlorophyll, currents), 16-day forecasts, and forecast model switching.