It depends on the policy of the individual landlord. The first thing you should do is discuss the situation with the LL to see if they are amicable to disolving the lease. They may have a waiting list and won't lose out on anything and will refund most of your money or at least not hold you to the entire lease.

Read up on the laws in your state and find out what you will be up against. You may need a lawyer if the LL won't waiver on the contract and the two of you are not able work things out to a mutual agreement.

There is not much chance you would get a refund. If you've rented the place for December 1, give the landlord a month's notice to vacate.
If you don't get the notice to him till tomorrow or Wednesday you should still be alright, he/she may charge you a late fee for giving it late.
Hope you didn't sign a lease of any kind or you're stuck with the place.
Suzan J

sjarz, if you READ the post by OP he DID sign a lease. He is legally responsible for an entire year of paying rent on the place.

Depending on how fast the landlord can rent the place again, there may be money to be paid back.

Since the place was recently advertised as being for rent there is a good chance that many people applied to rent it and the LL has a list of people to possible rent it out to. If the landlord can rent it out right away the security deposit will be refunded since there was no damage to the place. The law says that a landlord cannot collect double rent in this kind of situation. So if it is rented immediately the first months rent will also be refunded. There may be a *cancellation fee* applied if it is written in the lease or if the state laws allow it. Check the laws in your state. If it cannot be rented out in a timely manner the first months rent will be lost and possibly the security deposit if it take two months to rent. If it takes three months to rent out the LL may sue. But I just can't see that happening. A landlords interests would be best served by renting it as soon as possible.

Dilly Dally please excuse my blunder in writing what I did about the lease, obviously I didn't read that correctly.
I wonder if you could tell me, WHO died and made YOU the Forum police?
Suzan J

I did not do anything that would fall under the definition of "Forum Police". No need for a personal attack.

I posted advice to the OP addressing their concerns. The advice I gave was sound. You disagreed with my advice and did not have the facts of the OP in order. I then wrote a more detailed post explaining the steps to be followed for the OP. All in all there is no way to give a succinct answer to any of these questions posted about leases in a general forum, since every lease is written differently, and every state has different laws. I have no idea what the leasing laws are in Canada where you live. Nor do I know all the laws in Pennsylvania where the OP lives.

The only thing a person can do in a situation where they want to break a signed lease it to find out the laws in their area, and then talk to the landlord, and if that does not work, get a lawyer.

Well put, Dilly_Dally!