ΔE 16.9, loose: different enough that you should pick on purpose. Moonbeam Yellow is a little lighter, much more saturated than Dirty Yellow.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Moonbeam Yellow is a little lighter, much more saturated than Dirty Yellow.
The same difference applies the other way round: Dirty Yellow 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.
See Dirty Yellow on the colour wheel See Moonbeam Yellow on the colour wheel
All matches: Dirty Yellow equivalents · Moonbeam Yellow equivalents