I know it wasn't 5 degrees above freezing today in the Phoenix area (although I'd take that over what's being forecast next week):
From what I can tell the temperature data from KCHD just wasn't available, but the Rachio app misinterpreted the unavailable temperature:
When I switched to a different weather station that did know the temperature, things looked normal again. Maybe the Rachio app could handle the translation of a "NA" temperature more gracefully? I didn't try this on the web app, so it's possible that it's specific to iOS.