Your post does not indicate on which date of the month your lease requires payment of rent. Was your rent pro rated at the commencement of the lease so that you subsequently pay on the fist date of each month? If not, I would say you have to pay the full month at the end of the lease. Typically, you as the tenant must pay the full month of rent when it is due. The rationale is that there is no guarantee that you actually vacate on the last date of the fixed term lease.
Frank W. Chen has been licensed to practice law in California since 1988. The information presented here is general in nature and is not intended, nor should be construed, as legal advice for a particular case. This Avvo.com posting does not create any attorney-client relationship with the author. For specific advice about your particular situation, please consult with your own attorney.
If by the terms of the agreement your lease term expires on the 19th, you do not have to pay rent for any time past the lease term - but only if you vacate on the 19th. However, if you plan to remain in possession, certainly you have to pay the full month. It all revolves around the intent of the parties here. If either party wants the tenancy to terminate on the 19th and if possession is returned that day, then you pay the pro rated amount. Otherwise, you pay the full month's rent. If the landlady accepts rent for the full month, she has impliedly agreed to a month-to-month continuation of the tenancy.