I've bought licenses for both Global Warmth (first) and WeatherPop (second); WeatherPop is better because it's cheaper ($8 vs. $19) and it allows input from various weather sites (GW apparently allows only one source). I also prefer having WeatherPop in the menubar, out of the way, whereas GW stays in the Dock.
In short, Global Warmth is OK, but WeatherPop is better.
Global Warmth
monitor global weather in 5 different ways
Version: 2.3.3