Lord, this game is jank.
Would be nice to get more feedback about which room is the ghost room.
And the whole cauldron deal is just
bad, imo.
Freezing temps are jank, as well.
Could show freezing temps, but they end up not actually being one of the evidences.
If you're standing where the ghost currently is then it shows freezing, but it's only freezing temps if it's below 0C in the ghost room. The ghost room is always cold (like 10-15 degrees colder than every other room), but freezing temperatures is pretty obvious given it's a negative number.
If you're either too lazy to run around with a thermometer, or you're playing a big map, just go have a site assistant to do it (you have to unlock them, but tbh the red haired tomboy in the school is the easiest, just order food and outrun her, and if she surpasses just use x).
The cauldron thing is fair, but I don't think the temperature is that confusing. At the current state of the game, only like...one or two ghosts even have freezing temps anyway tho, so I wouldn't worry about it.