Weather apps must be among the most plentiful categories of software for iOS and the Mac. Every week or so, I see some new ones. It was inevitable that the very nice-looking Yahoo Weather app for iOS would catch developers' attention, so now we have Beautiful Weather for the Mac, a US$1.99 app available through the Apple app store.
The app uses a similar design language to the Yahoo app, and it picks some images from Flickr to match the location you are getting the forecast for. The app gives you the current temperature, the predicted high and low, the windspeed and the chance of showers. On the right side of the screen is an hour-by-hour forecast that looks ahead 12 hours. You can specifiy up to 12 cities for display, and if you have a trackpad, you can swipe between them.
The app is OK as far as it goes, but it has some weaknesses. There is no humidity display, no sunrise or sunset time, no forecast (!) for tomorrow or any other future day and no radar display. That seems weak for a weather app that costs money. The app does give an option to display your main city in the menu bar, but clicking on that does not bring up the app, unlike some other weather apps. The hourly forecast is nice, but if there is anything bright behind it, like an image of clouds, you can't read the numbers or see the icons.
I talked to the developer about these issues, and he said the missing features would be added soon. If you are looking for something a bit more complete, I would draw your attention to Mac apps like Clear Day ($3.99), Weather Dock ($1.99) or Living Weather ($2.99). If you'd like a menu bar-based weather app that is free, grab Meteorologist, which is an open-source app. It's mostly reliable, although sometimes it doesn't update correctly.
Beautiful Weather has promise, and looks nice due to the photos that keep updating, but it needs more information and features for a paid app. Beautiful Weather requires Mac OS 10.7 or later, and a 64-bit processor.