A lot of weather apps can be battery hogs, but most allow you to customize update intervals and location types... It is inexcusable that some basic weather apps access your GPS to get your location. Unless you are using an app like Nooly or Arcos, which tries to tell you almost to the minute if it will rain, apps pretty much only give you your local regional forecast, or at least the forecast at the closest weather station that they report for. In instances like that, network based location is more than suitable.
And for most cases, an interval of less than 3 hours is a waste of time. There are some exceptions, of course, like if you live in Tornado Alley, but even then, that's that the EWS alerts are for.