Banana belt and Sausalito is a bit of a stretch. Take a look at a TERRAIN map of Sausalito, CA at http://maps.google.com and you can see that the most sheltered part of Sausalito is in the north.
The part of Sausalito nearest the Golden Gate, facing east, is most exposed to marine influence, most subject to fog, and is probably what you mean by questionable. MIcroclimates change, highs get higher and lows lower, as you move north and away from the open water.
Topography and air circulation create different microclimates. That part of Sausalito facing Richardson Bay will have the warmest spots where the blocking ridges are sufficiently high.
Many folks find Sausalito weather too cool and prefer more sheltered areas. It is a very personal preference.
Geography is my thing. If I can help further RSVP.