ΔE 41.3, loose: different enough that you should pick on purpose. Violet Wash is a little lighter, much more saturated, warmer than Tempest Blue Wash.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 41). Violet Wash is a little lighter, much more saturated, warmer than Tempest Blue Wash.
The same difference applies the other way round: Tempest Blue Wash is a little darker, much more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Tempest Blue Wash on the colour wheel See Violet Wash on the colour wheel
All matches: Tempest Blue Wash equivalents · Violet Wash equivalents