@rongross The discussion in this thread is regarding automatic weather adjustments. There are only two ways a controller can reasonably do this: direct weather data via a weather station or online weather data from public weather stations. OpenSprinkler achieves automatic weather adjustments using the online method.
Therefore, this portion of the controller operation reaches out and grabs an adjusted watering level for the user selected method (eg. Zimmerman) and for the local weather at that time. Now keep in mind, the controller only polls for this value at intervals and stores the value locally meaning it will still have all the information locally to run without a connection. The default watering level is 100% and based on weather conditions the algorithm will scale between 0 to 200% which adjusts the duration of each stations run time.
I hope this helps!