Long parka in technical fabric
A fabric is water repellent after special treatments to make it resist water: the drops of water do not remain on the fabric, but slip away. Water-repellent fabrics have a certain degree of porosity so they are permeable to air and water vapor. They allow the passage of water when the hydrostatic pressure is high (for example during heavy rain).
A waterproof fabric prevents water from entering thanks to a membrane / lamination treatment. Water repellent and waterproof are not synonymous. Choose a waterproof garment to face heavy rains and seasonal storms.