Winterize your irrigation system by attaching an air compressor and using this tool, in tandem with your Rachio controller, to continuously cycle through your zones to blow them out with air. A wait time between each run allows pressure to build back up in your compressor and sprinkler lines; choose a long enough time to allow your compressor to periodically fully recharge.
This tool runs entirely in your browser and does not send data to any server other than Rachio's API.