If using passive solar design, thermal mass indoors is helpful to reduce temperature swings. Tile flooring on a slab is the most practical means. Passive solar in a warm climate should be skewed to provide shade much of the year, but most of the southern region does have a winter, so glass with strategically sized overhangs is a way to get shade in the summer and some free heat in winter.
However, thermal mass building systems have limited benefit here and are much more effective in places with wide day and night temperatures swings (e.g. New Mexico).
