When will KDE 5.13 be available to install?
It is included in the 13062018 ISO - which is being tested now (see https://openqa.opensuse.org/tests/).
Coming a.s.a.p. like always. In fact “a.s.a.p.” is the onely honest answer one could give here, and re. Tw in all other cases.
We see these questions more often here and on other platforms. Actually, when running Tw I don’t see the point of asking. KDE/Plasma gets released upstream, upstream flows into OBS, OBS starts building packages, packages are pushed to Tw, a new Tw snapshot is being built, pushed to openQA and tested, and after succesful tests the snapshot gets released. This means, you will always have updated packages as soon as our infrastructure is able to produce them. Just rely on that fact and be patient when it takes a couple of extra days. Tw is already bleeding edge.
If you really want to know, take some time to dive in the wonderful world of OBS / openQA and you can see the actual status / progress of what’s coming up.
In all other cases, wait-and-see is the best choice.
EDIT: And at the time I posted it, in comes the message “[opensuse-factory] New Tumbleweed snapshot 20180613 released!” 
Thanks, that’s what I thought. I’m new to Tumbleweed and like it very much. 
I just got the notification for the 5.13 update. Downloading and installing as we speak!
Just did the update. KDE 5.13 is installed. Thanks.