My son is nearly 2 and throws all blankets out of his cot most nights, so I'm reliant on clothes only to keep him warm. I did try his growbag on him last night and he immediately climbed out his cot with it on, the poppers on the shoulders came unpopped and he stepped out of it 
Tonight his room is 22 degrees. I've put him in a short sleeved vest, a sleep suit with a footless sleep suit over the top and a thin jumper. So lots of layers basically but I have no idea if he is snuggy.
If you have a toddler that won't sleep under a blanket or duvet, what are they wearing?
Thanks xx