Should my rent be prorated if I give notice in the middle of the month if I am a month-to-month tenant?

I think that you may not undertsand the notice requirement here.  If you are a month to month tenant you have to give one month's notice that you are moving (preferrably in writing and with a few days leeway).  Let me illustrate.  If you wish to leave on September 1st you need to give notice by August 1st at the very least.  You can give it in the middle of the month but that would be the month of JULY, not August.  When you pay your rent governs.  If you pay on the 15th then you have to give notice by the 15th of the month for the next month.  Otherwise you woe the rentfor the onth that you are in AND the next month and until you give proper notice.  Good luck.