The product details often include mentions of waterproof and breathable material. What does "breathable" mean?
Breathable fabric enables very active children to feel comfortable. The moisture that builds up on the skin during physical activity is able to escape through small pores in the fabric rather than remaining on the skin and making the child feel cold. Moist skin gets cold up to 20 times more quickly than dry skin, so the best waterproof materials are also breathable. Material breathability is expressed in g/m2/24 hours: the number of grams of moisture the fabric allows through an area of one square meter in one day.