ΔE 10.0, fair: the same colour family, but not a straight swap. Dark Blue is a little darker, cooler than Dark Sky.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Dark Blue is a little darker, cooler than Dark Sky.
The same difference applies the other way round: Dark Sky is a little lighter, warmer.
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 Dark Sky on the colour wheel See Dark Blue on the colour wheel
All matches: Dark Sky equivalents · Dark Blue equivalents