As far as I remember from my learning, before the name of a day the preposition "on" should be there. For example:
He'll be there on Sunday. He was there on Sunday.
Then my question if this rule is also valid when the word "every" exists?
For example:
"I am on every Wednesday at the college."
Or should I omit the preposition "on" from it?
Best Answer
When, if ever, have you seen that particular construction? “I am on every Wednesday…”?
Adverb phrases that express time go either at the beginning or at the end of a sentence.
The following is very awkward
Likewise, the time expression "every Wednesday", is no different
The preposition on is used before days of the week, before specific parts of the day and for dates.
https://www.englishclub.com/grammar/prepositions-at-in-on-time.htm
There is, however, one usage of “on every + [day]” that sounds idiomatic. When we mention the days and times of TV or radio shows. For example,
Here, the preposition "on" refers to being broadcast by (a radio or television channel) e.g. ‘a new twelve-part TV series on Channel 4’, ‘The show will be broadcast on CBS on December 26th.’