The shower, we went to bed late. There was also a rainstorm that night which skews things, but it's curious that the shower will actually raise the humidity of the whole house for hours after it's been used.
I used AHT21 I2C modules from Aliexpress https://www.aliexpress.com/item/1005002613543870.html . I think the one that failed last fall was a bad solder joint but I had a spare AHT21 board and ESP8266 so I just replace the whole unit.
The shower, we went to bed late. There was also a rainstorm that night which skews things, but it's curious that the shower will actually raise the humidity of the whole house for hours after it's been used.