As global temperatures rise, cities need affordable ways to stay cool—white roofs offer one. Reflective coatings can lower indoor temperatures by up to 6 °C and reduce urban heat by 2 °C. Case studies from London to Delhi slums show clear benefits in comfort, energy savings, and emissions. These coatings are low-cost, easy to apply, and often community-led. Despite some trade-offs, white roofs are a powerful tool for cooler, healthier cities.