While -Current hasn't officially started, we have seen some changes in -Current tree for a while and i think it will keep going like this until eventually something break the compatibility with Slackware 13.0 towards 13.1 release.
Pat usually never decide a fixed date for Slackware release. He will release it when it's considered ready and stable enough for production use, so let's just take this month's poll to predict when will next Slackware 13.1 be released.
Please note that this is just a poll and it will not have any effect of the real release date of next Slackware (probably 13.1). The decision is still on Pat's hand.