Lighthours

Lighthours is a term used chiefly in historical and nautical contexts to denote the period during which a lighthouse is lit and serves as a navigation aid. In older navigational practice, lighthours were determined by the keeper or the vessel's schedule and could vary with the seasons, weather, and local regulations. With the advent of automation and remote monitoring, most lighthouses operate continuously, and the explicit concept of fixed lighthours has become largely of historical interest. Some archival logs and nautical almanacs record lighthours as the time of illumination to help mariners understand beacon availability in specific ports or passages, and to document maintenance cycles.

Historically, a lighthouse might be lit from sunset to sunrise, or on a more variable schedule designed to conserve fuel or to reduce light pollution in colonies or urban areas. Weather conditions such as fog, storms, or cloud cover could extend or shorten the effective lighthours when the light appeared brighter than needed, and fog signals could operate on separate schedules.

In contemporary practice, lighthours are rarely a live navigational constraint but appear in historical studies, regulatory records, and heritage sites. Modern maritime navigation relies on automated lights, GPS, and standardized light characteristics rather than manually observed schedules; nonetheless, the term persists in archival material and in discussions of lighthouse history.