You basically want to look at the goggle lens specs and see what the VLT %, or how much light they allow through..as well as any other enhancements like improved contrast.
In general a high VLT between 80-100% are for night skiing, or darker/dreary conditions. Personally i prefer these types out here in Oregon because most of our good snow days it is very overcast with dark clouds, and sometimes foggy at the top. Clear lenses, and usually yellow lenses are in this category, depending on manufacturer.
Lenses like Persimmon(orangish) are in the 50-60% range and are considered all condition lenses..they arent great at light or day, the jack of all trades goggles...they do everything good enough. I also have a set of Persimmon lenses for really bright days, which aren't often here.
Anything lower than 50% is generally going to be a goggle for bright blue skies sun beating down on you days, if thats what your weather is like usually they might not be a bad idea...i would only need these for spring summer boarding, but Persimmon does the job fine too so i havent bothered.
different companies also have different additions, like higher contrast, or polarized goggles. In general high contrast is always a good thing to have, and polarized lenses good for bright conditions where there will be lots of glare off the snow...
Oakley has a kind of cool little flash thing showing generally how all their lenses will look like...
Oakley A FRAME Accessory Lenses available online at Oakley.com