Annual account about chap in Los Angeles (7)
'annual' is the definition.
(almanac is a kind of annual)
'account about chap in los angeles' is the wordplay.
'account' becomes 'ac'.
'about' indicates putting letters inside.
'chap' becomes 'man' (I've seen this before**).
'in' is an insertion indicator.
'los angeles' becomes 'la'.
'man' going within 'la' is 'lmana'.
'ac' enclosing 'lmana' is 'ALMANAC'.
(Other definitions for almanac that I've seen before include "Statistical annual", "Calendar with detailed information", "Annual reference book", "issue every year", "Annual containing information, Old Moore's say".)