Excelsior

Although you can plainly look at the forums for auction information, to cut down on the when is the auction spam perhaps a [auction command that would tell you when the next auction is? -Ashlee

Well it's usually announced on town criers. For some time now it's been every 2-3 weeks, usually on a sunday, usually at 9PM shard time

So if anyone asks for when the auction will be, just refer them to the nearest towncrier. If an auction is officially set on a schedule, then it should be there.