With that in mind, the IRS released another advisory yesterday, December 27th, in which they informed taxpayers of the conditions that must be present in order to deduct the pre-payment of 2018's property taxes from your 2017 return.
The advisory states that: "whether a taxpayer is allowed a deduction for the prepayment of state or local real property taxes in 2017 depends on whether the taxpayer makes the payment in 2017 and the real property taxes are assessed prior to 2018."
Basically, this means that you can only deduct the taxes that you paid in 2017 on assessed real estate tax bills. So if your property is re-assessed every summer, you can only deduct about a half -year's worth of property taxes.
You can read the entire announcement here.