California part time resident

[Linda Lz]

My son moved from WA to CA 7/14/18, the majority of his 2018 income was in CA.  He returned to WA 7/16/19 and started working for a WA company 7/29/19.  On his 2018 return, under Personal Info, do I list his State of Residence as California since he was there on 12/31/18? or do I list his State of Residence as Washington as he is back here.  I had originally prepared his tax return while he was still in CA but had not yet sent it in.  TurboTax determined that he should be filing a CA 540NR.

He will have both WA & CA income to report in 2019. My main concern is protecting his 2019 WA earnings from CA taxation.

[Critter]

It will not make a difference really ... I would file a part year CA return or a non resident return ... either way will get the same bottom line.