Cloudy Sky vs Natural Flesh

How close are they?

ΔE 19.1, loose: different enough that you should pick on purpose. Natural Flesh is a little lighter, much more saturated than Cloudy Sky.

Can I use Natural Flesh instead of Cloudy Sky?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Natural Flesh is a little lighter, much more saturated than Cloudy Sky.

Can I use Cloudy Sky instead of Natural Flesh?

The same difference applies the other way round: Cloudy Sky is a little darker, 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.