Water level
Lake Ontario (Lake America) Water Level
The current Lake Ontario (Lake America) water level is measured in feet, referenced to IGLD85 (International Great Lakes Datum of 1985), the standard reference across all five Great Lakes (see the method note below for how this page confirms that datum). This page shows the most recent reading from NOAA CO-OPS (Center for Operational Oceanographic Products and Services). As the site collects readings over 30 days, a trend chart will appear here so you can see whether levels are rising, falling, or stable. A plain-language note on what drives day to day level swings is planned but not yet sourced, so this page does not include one. Knowing the current level helps boaters understand water depth and aids navigation planning.
The Great Lakes standard reference is the International Great Lakes Datum of 1985 (IGLD85). NOAA's CO-OPS API returns IGLD85 directly for Lake Ontario when queried with datum=IGLD, confirmed live on 2026-08-28 for station 9052030 (Oswego), so readings on this page are labeled IGLD85.
This page does not yet explain what drives day to day changes in lake level. That explainer is waiting on a proper source and will cite it when it is added.
A 30 day trend line appears here once the worker has stored 30 days of readings for at least one Lake Ontario gauge.
Source: NOAA CO-OPS, api.tidesandcurrents.noaa.gov