Thermal Wind

Thermal wind is wind produced by temperature difference rather than by weather systems. Land heats faster than water under a clear sky; the warm air over land rises, and cooler air from over the water flows in to replace it. The result is the sea breeze that switches on at many spots around midday and blows until the land cools in the evening.

Thermals explain the daily rhythm of some of the world's most reliable kite destinations. Tarifa's Poniente afternoons, the Ionian channel winds of Greece, Lake Garda's Ora, the Egyptian summer machine at El Gouna: all thermally driven or thermally boosted, which is why locals talk about clock time as much as forecasts. A classic thermal day starts glassy, builds a rideable breeze by early afternoon and peaks before sunset. Where a synoptic wind blows the same way as the thermal, the two stack, turning a forecast 14 knots into a real 20.

For planning, the practical skills are two: learn your spot's thermal signature (which months, which hours, how many knots above forecast), and read the sky, since a cloudless hot day over the land is the engine that makes the afternoon deliver. Forecast models routinely underestimate local thermal effects, and local knowledge routinely beats them.