She suffered 216 stab wounds when she was allegedly attacked at the family's home in Ravensbourne.
The case was moved from Dunedin to Christchurch in February, after an application by defence counsel Judith Ablett-Kerr, QC, but the reasons for the move were suppressed.
Weatherston was ordered to stand trial after a depositions hearing midway through last year at which 17 witnesses gave evidence.