Have been using the app called WeatherBug for the past couple of years and really like it. It's free and no annoying ads or popups to deal with. You can store various cities where you want to view the forecast (i.e. where you live and places you might travel/vacation). Has hourly forecasts and live radar weather map that lets you see approaching storms/bad weather. Forecast more then 2-3 days out are inaccurate no matter who is providing them. There are far too many random variables the can impact future weather. The future radar projections are also not very accurate and I don't bother using them.
There are probably hundreds of apps for weather, so you just need to find the one that works best for you. I can't see any value in paying for that, so just look around and see what is available. I find that things specifically formatted for the phone work way better then trying to view some website. Typically, the formats aren't compatible for phone use and/or the displays/word-wrapping gets all messed up.