Sea breeze
A daytime onshore wind driven by uneven heating of land and water — the engine of most summer coastal sessions.
Also known as: thermal breeze, onshore thermal
A sea breeze is a daily wind that flows from sea to land. The sun heats land faster than water; warm air over the coast rises, cooler marine air rushes in to take its place. That horizontal inflow, perpendicular to the coastline, is the breeze.
A textbook cycle starts light around mid-morning, ramps to 15–25 kt by mid-afternoon, and dies inside an hour of sunset. In the Northern Hemisphere the wind clocks right through the day (Coriolis veer), so a noon onshore is often 20–40° off-axis by 17:00.
Sea breezes power most summer coastal sessions in temperate latitudes. They reward riders who:
- Watch the inland temperature, not just the wind forecast
- Trust high-resolution models (ICON, AROME) over global GFS — coarse models smooth the coastline and miss the breeze
- Plan around the afternoon peak, not the dawn check
Full mechanism, ingredients checklist, and where it rules a season: Sea Breeze 101.
Related terms
- Land breeze A nighttime offshore wind driven by the reverse of the sea-breeze cycle — cooler over land, warmer over water.
- Thermal wind Wind driven by uneven solar heating on a daily cycle — sea breezes, valley breezes, anabatic upslope flow all belong to this family.
- Gradient wind The large-scale wind driven by pressure differences between weather systems — the synoptic background flow that everything else rides on top of.
- Gust factor The ratio of peak gust to average wind — the single most useful number for telling smooth wind from a fight.