Rain umbrellas and sun umbrellas (parasols) serve different purposes - rain umbrellas are used to shield from rain and snow while parasols are used to protect from intense sunlight. The two umbrellas also differ in their materials, with rain umbrellas having thicker, waterproof fabric and parasols having thinner fabric with UV-protective coatings. While rain umbrellas focus on resisting wind and rain, parasols have a more delicate appearance suited for blocking harmful UV rays in summer heat.