Can I publish for only Windows? I am planning to use C++ and SDL to make a game for the jam. (I will also provide the source code using premake). It's fine if I have to publish to Mac, but I'm not really in a position to publish for the web.

i have been in the previous jams and i think i only did for windows and its defenetly allowed but its judged by community vote and in a big gamejam like this it can be hard to get many people to play your game so there is defenetly an advantage to making as many people as possible able to play.  but its defenetly not necesary