I think it stays on for an hour... although it can be hard to tell if the temperature isn't that extreme, because the HVAC automatically ramps down as it approaches the target temperature.
related question: how many miles of range does the climate preconditioning eat up per hour in, say, (a) 96 degree sun, or (b) 10 degree cold? I will test and provide data regarding (a).
On our trip I saw about 1 mile of rated range for both heater and air conditioning for the extremes of 30 degrees and 92 degrees for every 15 minutes roughly and no, this wasn't more scientific than turning on the climate and looking at the app every 15 minutes.
