@hushyyy Hello, the list of NOAA's radar locations indeed includes South Korea (and other non-USA locations as well). All the listed radar sites upload their data to a single endpoint (Amazon S3). Our program collects all the available data in S3 and then processes/displays them in correct position on the map (radar data are geo-referenced, they contain information of their origin's location).
So basically, this is a "side effect" :D. We were quite surprised too when we saw coverage of these locations in the first radar prototypes. We expected that only USA would show up, but later on we found out that there are much more remote locations that provide data for NOAA (hence, the link I posted at the beginning of this reply).