Morning is different from dawn.
Dawn is when the sun rises. Morning is when you rise.
Oh we were having some sort or a pedant-off contest here, I didn't actually say "AT dawn". I meant to write "closer to" in there as well, but either I fucked it up with typing on mobile or I'm just so high my brain skipped a few words. Both have been known to happen on Saturday evenings.
Oh yeah there's a hundred other things there as well, but *studies SEEM to indicate that you shouldn't take vitamin d at night / in the evening / close to your bedtime. And since our organs also have circadian rhythms or function on oir circadian rhythm and it takes a while to ingest all of the supplement, perhaps a bit before a bit before your bedtime? Perhaps like, make it a routine to do it nearer the beginning of the day than the end of the day.
Science seems to agree.