What are earth sweats?

Earth sweats occur when the humidity is on the rise and wood, porcelain, metal, and even stone may exude moisture. They have come to be seen as predictors of rain. Wooden beams and furniture, china dishes, stone, and brick all may sweat when rain is near. Oiled wood especially, such as a salad bowl or a weaving loom with linseed oil on it, sweats easily.