Converting a traditional IRA to a Roth IRA before the end of the year is a no-lose situation. The value of the traditional IRA (minus the amount of non-deductible contributions) is taxed as income upon conversion. If you think the value of the IRA might increase, it is better to make the conversion now rather than later.

However, if the value of the IRA decreases after the conversion, you can revoke the conversion as late as October 15th of the following year, and make another conversion at lower cost. This is a unique situation since the IRS allows you to make an election with hindsight – effectively giving a choice of times to make it on the best terms.