On a hot/humid morning, my brand new 2019 Kia Sorento emits white smoke on startup. After driving for about 3 minutes it goes away. Is that normal?
Yes, this is usually down to the water vapor in the exhaust gasses.
When they come out of the tailpipe, they tend to be hotter than the surrounding ambient air so the water vapor in the exhaust gas starts to condense giving the white vapor...
The engine and catalytic converter has, after 3 minutes & normal driving, got closer to "normal" operating temperatures which also changes the ratios of the components of the exhaust gas and its temperature on exit.
Yeap, that is normal condensation and moisture that had collected in the exhaust system.
Air will seep into the hot exhaust and condense over night. These fine water droplets will start to evaporate when hot exhaust gasses passes by on the morning start up. Most of the water is collected in your muffler which tend to rust over time.
Hope that helps.