I did know that the NO church cancels days of obligation that fall on either a Saturday or Monday Just what the world needs - fewer Holy days!
Marsha
This applies to the Novus Ordo in the United States. I don't know about other countries. The exception is the Feast of the Immaculate Conception, because this is the patron saint of the United States, and Christmas Day. A year or two before I found tradition, Christmas as New Year's fell on Saturdays. Christmas was a holy day, of course, but they didn't even mention New Years Day as a day of obligation at all.
Older missals will tell you the rank of Feasts. I don't know whether there is a website that explains the Roman Calendar.