Seasonality Core 2.0 is a Mac app any weather aficionado should have. That's because it's probably the most complete and detailed weather software I've ever seen on the Mac. The interface is simple enough. A list on the left allows you to enter any number of cities around the world you want to track. It's got 34,000 built-in cities in more than 200 countries. Additionally it allows you to add custom locations using ICAO stations,
