WCmore's Graphs
From webCoRE Wiki - Web-enabled Community's own Rule Engine
twcweather.forecast.daypart[0]
Twice a day the data stored under twcweather.forecast.daypart[0] changes. Preliminary tests over 15 days (31 data points) shows it changes sometime between 3:00 and 3:30. Here is a quick graph to show how much it varies day by day. (the numbers show how many minutes past 3 AM/PM)
The change over can not trigger a piston, so to determine the time it changes I have to query it multiple times, and take note of when it changes. The long bars is when I was checking every 5 or 10 minutes... The short bars is when I was checking every minute (to narrow it down more precisely).