I bought a size 4T for my son who is 42" and 39lbs and they fit almost perfectly with little room to grow (thanks for the adjustable waist).
Boys' Adidas Active Sports Tricot Athletic Clothing
45 Review
π Fruit of the Loom 6 Pair Cushion Ankle Boys' Clothing: Comfy and Stylish Selection for Active Boys
57 Review
π Boys' Outdoor Climbing Convertible Trousers - Waterproof | Clothing
47 Review
Waterproof Cozy-Dry Rain/Snow Pants for π§ Kids by JAN & JUL, with Fleece Lining
64 Review