humidity
Humidity is how much water is being held in the air.
Humidity makes the temperature and weather outside feel different to us (more humidity= feels wetter, less humidity= feels drier).
Humidity is similar to a sponge soaking up water. The more water the sponge has to soak up, the wetter the sponge will be. The less water a sponge has to soak up, the drier it will be.
Sometimes when it is humid out, windows may look like this!