It is definitely the humidity. I moved into a new house in January.
My old house had a humidifier on the furnace and the new one did not. After one week I noticed all my planes had terrible wrinkles and everyone in the house was complaining of dryness and itching.
I had a humidifier installed right away on furnace and it was set to 35%.
One week later everyone was happy including me as my planes were nice and tight again.