There are a ridiculous number of iPhone apps that can tell you the weather. I have purchased a whole bunch of them, partly because weather apps are inherently useful, but also because whenever I find one with an interface or a feature that I like, it is often not long before another one comes along that seems like it might be better. But for quite a while now, I've stuck with just one Weather app on the home screen of my iPhone: Weather Line, which is currently on sale for only $1.99. Here's why this has been my favorite weather app, and perhaps it will appeal to you as well.
A line is worth a thousand words
Weather Line shows you a series of hours, days or months, and then displays the temperature for each day. Many apps do this, but what I love about Weather Line, and what gives the app the name, is the line that connects the temperatures. The line means that your brain does not even need to process the numbers. You quickly see that a line is going up to indicate that it is getting warmer, a line going down to indicate that it is getting colder, or the line is relatively straight if the temperature is staying about the same.
For example, in the following images from the Hourly view, I can see that the temperature starts at 80° and then slowly rises to 86°. I wouldn't use the app if it didn't include the numbers, but it is the slight incline of the line that helps me to quickly see the gradual increase in temperature. Moreover, the lines are yellow when it is mostly sunny and blue when there is a chance of rain, another quick and helpful visual clue. You can tap on any hour to get more detailed information about the temperature during that hour, such as what the weather will actually feel like, the chance of rain during that hour, the humidity, etc.
If you swipe from right to left, you can see the hourly forecast for the next 48 hours.
In the Daily view, you see the high and low temperature for each day, again with lines to help you see how the highs and lows will change (or not change) from day to day, plus blue or yellow colors to indicate rain or shine. I use this view all the time to get a sense of whether it is getting warmer or colder during the week. Tap on any specific day for a mini-forecast for that day at the bottom. The app was updated last week to show you the date in addition to the first letter of the day of the week, which was a nice addition.
On an iPhone 5s or earlier, you can see up to seven days on the screen. Although I use an iPhone 6, I have it set to the "Zoomed" view (Settings -> Display & Brightness -> View -> Zoomed) so that all of my apps are bigger and easier for me to see, but if you instead use the Standard view on an iPhone 6, a recent update to Weather Line will take advantage of that extra space to show an extra day. In the following images from my iPhone 6, the first one is in Zoomed mode, and the second one is Standard mode.
I am sure that you can also see the extra day on an iPhone 6 Plus, but I don't have one to test so I don't know if you only see the extra day when you are in Standard view.
The app also has a Monthly view that shows monthly averages for a city. I can see how that might be useful, perhaps for a city that you will be visiting. In practice, however, I rarely use this view.
Dark Sky forecasts
Dark Sky is an amazing weather app that provides very precise forecasts for the next hour in your specific location. If you are about to head out of the office for lunch, this is the app that lets you know whether you need to bring an umbrella. But other apps can also tap into the Dark Sky database, and Weather Line does so. Thus, at the very bottom of the screen, Weather Line tells you whether or not it will rain in the next hour. Tap that forecast to get a detailed minute-to-minute forecast of precisely when it will start and stop raining and how heavy it will be.
These Dark Sky forecasts are very useful and I use them all of the time. For example, I often find out that the rain is going to stop in a few minutes and then start up again, so I know that I can wait for a short window to go out without getting wet. Or, I can find out that it is just going to get worse, so I might as well go out now.
Although I also have the Dark Sky app on my iPhone, I love that much of its functionality is built in to the Weather Line app so that I can have everything that I need in a single app. (The Dark Sky app is still useful if you want to see a radar from the last few hours plus an excellent forecast of the predicted radar for the next hour.)
Weather Line has a few other features. For example, tap the information icon at the top right to switch to another city, or to add new cities to your list of favorites. You can also switch from Fahrenheit to Celsius.
However, the core of the app is just a single screen that I use to see the hourly, or the daily, forecast. I find this app to be incredibly easy to use, and I find that it is better than any other weather app that I have tried when I want to quickly see the current weather and how that weather will change in the future. Whenever I take a trip to another city, this is my favorite app for helping me to quickly figure out what weather I need to pack for.
I highly recommend Weather Line to anyone looking for a great weather app. It is normally $2.99, but I see that it is currently on sale for $1.99.