Downstairs/ upstairs
Which in is more humid? 
Discussion
If humidity % is the same, I’d guess there’s more actual water in the room with a cooler temp - just more of that water is in liquid form and not in the air, so if you heated that room to match the warm room, it would end up with higher humidity.
However, with identical % the warmer space probably feels more humid to a person walking through.
I could have that backwards but it seems logical 🤔
Hotter has more energy & holds more water, more water in the air upstairs, it will hit its dew point first
For both upstairs and downstairs relative humidity is equal: 56%. However air where temperature is higher (20.4 Celsius) accommodates more water, hence absolute humidity is higher there. Optimal health-wise indoor humidity is between 50 and 60%. When indoor humidity is higher than 60% problems with mould growth might appear.
Very well done, thank you