The Algarve's Sea Turns Colder Than the North Coast as Summer Upwelling Flips Portugal's Usual Temperature Map
The Algarve's sea is currently colder than the west and north coasts — roughly 18-19°C versus 20-21°C — an inversion of the usual summer pattern. The cause is the 'nortada' wind driving coastal upwelling, which pushes warm surface water offshore and pulls colder water up from the deep.