It's insanely warm. My 3 year old goes to a forest school, we live in Kentucky so it's not insanely cold but it gets down to 10(F) and his teachers actually asked me to stop wearing the t-shirt at all because he cried, it was hot and sweaty at 15 degrees and 5 cm of snow π . So far it's holding up great. Runs a little small, or maybe very true to size, other than that it should work with the base layer. It fits him well now, but I factored in room for growth and not a lot of extra space.
Pack of 6 Baby Soft Cotton Underwear for Little Boys - Dinosaur Briefs, Toddler Shark Undies, Children Truck Panties
41 Review
π¦ HLMBB Dinosaur Toddler Underwear Training | Boys' Clothing for Easy Potty Training
44 Review
π Russell Athletic FreshForce Protection: Boost Your Boys' Performance with Assorted Clothing
49 Review
Comfortable & Practical City Threads Underwear: Sensitive-Friendly Boys' Clothing
47 Review
Arctix Youth Pants Reinforced: Large Boys' Clothing for Active Adventures
46 Review
Boys' Adidas Active Sports Tricot Athletic Clothing
45 Review
Waterproof Cozy-Dry Rain/Snow Pants for π§ Kids by JAN & JUL, with Fleece Lining
64 Review
π Bold Pack Sleeve Active Hoodie Sweatshirt Set for Boys' Clothing - Stylish and Comfortable!
47 Review