SEA-SLC on Delta. 737-800.
Freezing outbound… luckily had ski jacket with me.
Sauna on return… heard so many people complaining but oddly the cabin seemingly only got even a bit hotter as the flight went on.

I don’t understand this. There had to have been 20+ degree difference in temp. Same aircraft, same airline, sat in roughly same area of the plane both ways. What drives one captain to freeze pax and another to toast them?