For those looking for an easier way to blow out their systems in the winter or maintenance throughout the year, I've revived the Winterizinator.com site that lets you turn on/off zones at random (Thanks to Varun Mehta for the original site years ago). Just enter your API Access Key available in the app.rachio.com user menu and click Go.
You'll see all your zones and tap the button to turn on a zone, click another zone to switch to that zone or turn all zones off.
I hope to keep the site active until Rachio can at least add a 'Skip to Next Zone' button when it's running a manual watering. Guess I could create my own AppleWatch app next. Lol