The São Sebastião Channel

The São Sebastião Channel is a marine passage with 25 km of length, 2 to 7 km of width, 40 m of maximum depth, located between the Island of São Sebastião (Ilhabela municipality) and the continent (São Sebastião municipality), in the northern coast of São Paulo State, southeastern Brazil (23°43' to 23°52'S - 45°20' to 45°27'W).
The weather is subtropical. Currents in the São Sebastião Channel are driven
by wind. Coastal water occupies the upper layer of the sea during most of
the year. Water temperature oscillates between 15 and 28°C (generally higher
than 20°C at the surface). The region is influenced by the warm (22-28ºC) water of the Brazilian Current flowing southward, by the colder (<13ºC) and more saline (~36 psu) South Atlantic Central Water (SACW) that is upwelled on the shelf during the summer,  and by a cold (~18ºC)  and low salinity (<33 psu) water mass originating from the south  that enters the channel during winter.

Location of the São Sebastião Channel

More data on the physical characteristics of the São Sebastião Channel can be found in Oliveira & Marques (2007) [text in Portuguese].