I can’t recall seeing anything about this, just wondering if I should do the black garbage bag shroud.
I cover mine.
Skunkiness in beer is caused by reaction of isomerized hop acids with UV light. Cider has no hops, therefore you will not get the skunk. Whether UV light does anything else to harm cider, I don’t know, but I wouldn’t be too worried about it. Not anywhere near the same level of concern as with beer.
I know of the chemistry behind the skunk, Cooks Illustrated did a nifty article about it awhile ago. So, I will cover the cider out of paranoia, knowing that it probably isn’t necessary, but then usually things are best kept in the dark.
It may not skunk like beer, but light strike is still a big concern for ciders and white wines and can lead to off flavors. Mainly only caused by excessive amounts of UV, but no need to take the chance during bulk aging.