It kinda makes sense not to have a stock weather app on a wi-fi only iPad - it can only pull up info when it is connected, and not everyone has wi-fi in, say, their home, so it would lie there inactive. On a wireless version, its another story.
That said - as noted above, for those who do want a weather app (for wi-fi or data versions), the Apple app is pretty basic and its reporting destinations or information generally not as extensive as some other (often free) apps out there. I, for example, use The Weather Network app, and aside from the ability to have it 'follow me' a far as general locations are concerned, it happens to have a reporting station 2 blocks from my home, so that's my default location.
Granted, it can't use Notifications as an Apple weather app does, but I so rarely think about using Notifications on my iPad or iPhone, anyway.