What is the sun availability for the chaparral biome?

I am not sure what you are asking.  There is ample sun for the chaparral biome nearly year around.  The primary limiting factor is usually water.  Many of chaparral plants drop their leaves during drought periods.

The Californian chaparral receives the same amount of sunlight as the Mediterranean maquis, the Chilean matorral, Australian kwongan or mallee, or the South African fynbos. These are equivalent  subtropical to temperate Mediterranean ecosystems found around the world between about 30° and 40°  latitude. They are semi arid settings near a body of water. This combines to produce mild, moist winters and hot, dry summers that support evergreen forests dominated by evergreen shrubs.  Rainfall is limited and fog from the ocean provides most of the summer moisture
Chaparral climate
http://www.blueplanetbiomes.org/chaparral_climate_page.htm.
http://www.marietta.edu/~biol/biomes/shrub.htm
https://docs.google.com/viewer?a=v&q=cache:MOw3r2uQimsJ:www.bio.uu.nl/~boev/education/vegzones_world.doc+&hl=en&gl=us&pid=bl&srcid=ADGEEShzoKhZaJlgTdKvNTNHG_gfjd_DskgU8JTURtRwApTa2i0Z_DSzP4G6qytzcde2dxfbqXxd5S0a13Tc2IyXIojd4iy8tGsAKibOUR7HMLTdeWHmAgMFN2pBH6vZPlhzAq-adeYM&sig=AHIEtbS1orRRQ6KJu0vYYM32bEb_Xmrs0Q

The coastal chaparral band
https://docs.google.com/viewer?a=v&q=cache:jK_CTKOcNzAJ:www.fs.fed.us/database/feis/pdfs/PNVGs/California/R1CHAP.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESjZzsONXLyU4SOPPHDKmJbS84l5tqCstlv11qKvgMhTJ2r1OZq_QwiCSN_ZgcNFRE05Pp53GPBYhPtZpjv6tdbva78WipzEZgWdNLv0w1Ttvu5-syta7qdhGaTYU02uAWh19qrQ&sig=AHIEtbSyitQOO_-3NAoAQB3Cl3tJ5gaUaw