A gale warning is a weather advisory issued by national meteorological agencies to alert people of imminent or current sustained surface winds or frequent gusts in the range of 34 knots (39 mph) to 47 knots (54 mph) inclusive. Gale warnings are usually associated with deep low-pressure areas, but they can also occur in other conditions, including from anticyclones or high-pressure systems in the continental interior. The warning is issued to allow mariners to take precautionary actions to ensure their safety at sea or to seek safe anchorage and ride out the storm on land.

In the United States, the National Weather Service issues gale warnings for marine areas (oceans, sounds, estuaries, and the Great Lakes) experiencing, or about to experience, winds within the range of 34 knots (63 km/h; 39 mph) to 47 knots (87 km/h; 54 mph) . Two red pennants indicate a gale warning in the United States maritime warning flag systems, while the use of one such flag denotes a small craft advisory.

Gale warnings are issued by national meteorological agencies and maritime authorities to warn people who may be out at sea or near the coastline of hazardous conditions - occurring or predicted. The daytime display signal for a gale warning is two red pennants, and the night signal is white and red lights. Gale-force winds can create hazardous conditions at sea, endangering vessels and lives, and can also cause damage to property on land.

As climate change continues to influence weather patterns, the implications of gale warnings can evolve over time. Rising sea temperatures and changes in atmospheric conditions contribute to the increasing frequency and intensity of gale-force winds, posing challenges for meteorological agencies in accurately predicting and responding to these extreme weather events. Clear communication from authorities, along with community support, plays a vital role in helping individuals cope with the stress associated with potential weather threats.