ΔE 15.7, loose: different enough that you should pick on purpose. Cloudy Sky is a little darker, much more saturated than Brainmatter Beige.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Cloudy Sky is a little darker, much more saturated than Brainmatter Beige.
The same difference applies the other way round: Brainmatter Beige is a little lighter, much more muted.
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 Brainmatter Beige on the colour wheel See Cloudy Sky on the colour wheel
All matches: Brainmatter Beige equivalents · Cloudy Sky equivalents