Weather apps. I have TONS of them. I have ~350 apps on my iPhone, and moe that have been kicked out to make space. (The cool thing is, once you buy it, it's yours, whether it's on your device or not, and it's almost _always_ available on all your current and future devices, too. The exception being if it has a separate iPad-specific version, sometimes you have to buy both).
My absolute favorite forecasting app is Dark Sky. It tells you what the temp is now. It has a graph at the top that shows likelihood of rain for the next hour. It can be set to warn you when rain is about to start! It is VERY accurate. You can use it while traveling too- it detects your location.
Second favorite is Fahrenheit. It shows the current temp as a notification (red circle) on the app, without opening the app. It has a simple six-day view, which scrolls to ten, and expands when touched. You can set as many locations as you want, and flip through them. I use it extensively for shipping snakes, for watching temps here, in Memphis, and at the destination.
Weather On is an app that I never open. I have it set to deliver my daitly forecast at 5AM. It pops up the forecast, I read it. Love it.
Umbrella is similar. You touch it and it has a simple Yes or No answer to Do I need to take my umbrella? I have mine set to alert me at 5AM if I need to take my umbrella that day. It is decently accurate for yes, and VERY accurate for no.
I have two favorite radar apps. Radar Pro has the fastest updates. If you are watching severe weather, it has the most current info. But it's hard to look at. Radar US is my go-to radar app.
Lightning Finder is fun, but it requires a subscription, yearly. But it's cool to see all the lightning strikes close to my house.
Tornado is free and it will alert you to bad weather.