Based on the reviews I chose 7 (he currently wears 6) and it's too big. However, I think it's okay to grow up in it. Also, as others have said, it's quite thin for a sweatshirt (definitely not a Lands End item) so given the need for waxing and the thinness of the fabric, it's perfect for spring.
Splendid Boys Little Hoodie Heather Boys' Clothing in Fashion Hoodies & Sweatshirts
67 Review
Comfortable Amazon Essentials Disney Sweatshirt Hoodies for Boys: A Must-Have in Boys' Clothing Collection
65 Review
Get your Link on with Ya-cos Cosplay Hooded Hyrule Warriors Jacket β Green Zipper Coat
52 Review
Stylish Toddler Excavator Crewneck Sweatshirt: Boys' Fashion Hoodies & Sweatshirts
38 Review
Waterproof Cozy-Dry Rain/Snow Pants for π§ Kids by JAN & JUL, with Fleece Lining
64 Review
Arctix Youth Pants Reinforced: Large Boys' Clothing for Active Adventures
46 Review
π Boys' Outdoor Climbing Convertible Trousers - Waterproof | Clothing
47 Review
Funny Guy Mugs Tearaway Sweatpants: Playful Boys' Clothing for Fun and Active Days
49 Review