The region of the world in which the sun is directly overhead at least one day of the year is found within a band on either side of the equator from 23.5°N, and 23.5°S. These parallels are known as the Tropic of Cancer, and the Tropic of Capricorn, respectively. The portion of the world found between the Tropics of Cancer and Capricorn is known as the Tropics. The subtropics are the geographical and climatical zone of the Earth immediately north and south of the Tropics. The term "subtropical" describes the climatic region found adjacent to the tropics, usually between 20 and 40 degrees of latitude in both hemispheres. Most of what is known as the "Mediterranean Climate" (to be discussed later in the semester) zone of California is found in the subtropics, from around the Golden Gate Bridge south.
Hurricanes are tropical disturbances with sustained winds exceeding 74 mph. They form in the tropics in regions with ocean temperatures greater than 82oF (28oC) or so; clouds and precipitation from such storms can affect California and are a normal but infrequent occurence (~three times per decade or so). We'll be seeing some of these on weather maps and satellite images at the beginning of the Fall Semester.