Hi Dave,
The IP you are showing is our cloud server, weather.opensprinkler.com. This is used for more than weather adjustments though as the timezone resolution and daylight saving time calculations are done on the cloud server. We also use the cloud server to provide sunrise and sunset data. Basically, this server allows us to extend features without OpenSprinkler having to depend on many 3rd party services and delaying the query time.
Thanks!