alt Hacker News250 MB is exactly the sort of bloat you'd expect from this sort of daft web-browser-wrapper application, and Apple get it there. 1.2 GB, on the other hand, is 5x as much, and completely insane even when you start off with daft as your starting point.
Apple weather is fully native from what I understand. I suspect the 250MB comes from the video backgrounds they play. Arguably that would be a reasonable thing to sacrifice on low memory systems, you'd barely notice.