From Longman Dictionary of Contemporary Englisha week on Monday etca week on Monday etcBritish English, a week from Monday etc American English a week after the day that is mentioned The Reids are coming for dinner a week from Sunday. Keith’s coming home two weeks on Saturday (=two weeks after next Saturday). → week
Examples from the Corpus
a week on Monday etc• Suppose we say December the second, that's a week on Monday. 