My newest fave app is The Weather Channel app. It is very user friendly, nice looking and has all the pertinent information that I need. You can choose an hourly forecast, a 36-hour forecast or a 10-day forecast.
It has also helped us tremendously with my son who is thunder-obsessed. For the last three summers, we haven't slept through a single night because if there IS thunder, he runs in to our room frantically. But even if there isn't thunder, he would still wake up anticipating it. We had tried everything - positive reinforcement, taking things away, and maybe some yelling. When his pediatrician suggested that we check the weather before bed, I decided to let him check it himself on my phone. This was a big deal for him because he typically isn't allowed to play with my phone.