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