ΔE 26.5, loose: different enough that you should pick on purpose. Blue Mountain is a little darker, much more muted, warmer than Caledor Sky.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 27). Blue Mountain is a little darker, much more muted, warmer than Caledor Sky.
The same difference applies the other way round: Caledor Sky is a little lighter, much more saturated, 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 Caledor Sky on the colour wheel See Blue Mountain on the colour wheel
All matches: Caledor Sky equivalents · Blue Mountain equivalents