ΔE 9.7, close: similar, with a visible difference side by side. Sand is a little lighter, more saturated than Warm Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Sand is a little lighter, more saturated than Warm Grey.
The same difference applies the other way round: Warm Grey is a little darker, 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 Warm Grey on the colour wheel See Sand on the colour wheel
All matches: Warm Grey equivalents · Sand equivalents