tl;dr: Windows 11's built-in Weather app can consume over 1 GB of RAM—roughly 5x more than Apple's macOS equivalent—because it's essentially an MSN web app running on WebView2, spawning multiple Chromium subprocesses. The bloat is particularly problematic on 8GB systems, where the app can eat nearly 20% of available memory, and it also displays ads within the forecast interface. Microsoft has said it plans to build more native Windows apps, but hasn't confirmed whether Weather will be rewritten in WinUI.