See current rotation without playing

Solution 1:

There's two ways to do this.

The more "official" way is to log on to the official splatoon leaderboards site, then go to the Stage Info tab on the left (the purple one) if you aren't there already. This will tell you the current maps and ranked mode as well as ones in the future.

The other way is to use this unofficial site that pulls data off of the first site. It displays the current map rotation and current mode, as well as a countdown until the rotation changes, but does not show future rotations. (Also there's a button on the top left to turn off the embedded music!)

Update: Here is another site that shows the rotation. Unlike the site I posted above, this one also shows future maps!