The system will switch between them, choosing which is best at the time. In addition to the battery, it could turn recirculate off with high humidity in the cabin.
I've found if I've chosen Auto and pushed the AC button, it'll sometimes switch to recirculate for the first few minutes (dash indicates the switch to recirc too), then back to outside air. I'd concur, recirc is for special occasions, either to accelerate AC cooling, or due to stinky diesel in front.
I’m revisiting this topic. I’ve had AC on auto except when I’m getting close to home I turn the heat on. Seems crazy but I’m paranoid about the mold buildup. I’m already smelling a slight odor similar to my 2009 if I just use the AC as one normally would. Two days ago I manually switched to recirculate by pressing the switch because I was passing a very cloudy construction area. Now the only way I can turn off the recirculating air switch is to turn on the outside air switch. I guess this makes sense except now the switch light stays on. Before turning the recirculating switch on no lights were on. I don’t get it. Also just read somewhere that the rain sensor has been updated / relocated on the 2026 model. Probably improving on the sensitivity. I’m supposed to protect myself from seeing these updates. Ha!