Getting current weather on your iPhone lock screen seems like a really good idea. That's what the US$0.99 Lock Screen Weather app does. Tap a button on your iPhone and you'll get the current weather at your location, plus an extended 5 day forecast.
There have been other attempts to do this, like the Weather Lock Screen, app but the weather is not live and has to be updated every day. By comparison, Lock Screen Weather works pretty well. Give it your location (or any city you want weather for), run the app, and you're set.
The app also gives you an option for background sounds, like the ocean or a lake. However, those sounds run all the time, and I can't think of many people who would want their iPhone constantly making noise. Thankfully, that feature can be turned off.
There are some downsides. I've seen a few crashes, which makes it so the app doesn't run and you see your normal lock screen instead. I've also seen some issues where the app seems to interfere with the iPhone's sleep function.
Other than that, Lock Screen Weather does what it advertises. The weather does update, and that's what you want out of the app. I expect the crashes that sometimes happen can be fixed in an update, and then the app would get my highest recommendation.
Note: Some of our readers have suggested that the app weather page is actually treated as an album cover, and that even in silent mode the app is playing an empty track. If that is the case, running the app would have a negative effect on battery life. I have confirmed that playing music files crashes the app, so that gives credence to the claims being made. I've asked the app author for some explanation, so at this point, having already noted the crashing issues, it is not at this time something I would recommend.
A further note from app author Michal Sedlak confirms that he treats his weather screen as an album cover: "In order to display weather on the lock screen, we need to play at least low quality 'silence sound' to make battery drain as low as possible. We are working hard to improve this app in future updates."
Clearly, the app is making an end run around Apple to stay within the rules, but to accomplish something Apple does not really allow directly. I think the author should disclose his methodology in his write-up at the app store so people can choose if they want to trade some battery life for live weather.
Check below for a couple of screen shots that show what you can expect.