If I recharacterize a ROTH IRA to a traditional IRA, how long is the waiting period before I could convert that traditional IRA back to a ROTH IRA?

Note, you do NOT normally control the timing of either end of the transaction. Custodians put your letter of instructions into a que and process them. Your transaction can occur two weeks later. If you are a big cheese with your custodian and make a lot of noise, you may be able to get more timely action. For the next three weeks, most IRA back offices are swamped... so expect delays. It is probably not worth considering unless your stock portfolio decline is more than 20% in my opinion.

It's the LATER of 30 days OR the year after the year of the original conversion.

So if you are recharacterizing a year 2000 conversion now, it's 30 days.

If you recharacterize a year 2001 conversion, you have to wait until 2002 to reconvert.