Lightweight merino and 0.2-0.5 Tog baby sleeping bags are designed to be used for day sleeps in summer and the hottest nights of the year, usually for room temperatures above 25 degrees. A sleeping bag is a positive sleep association for babies and toddlers, so it's a good idea to continue to use a lightweight sleeping bag to indicate it's bedtime to your baby.  They may only need a nappy or a nappy and a singlet on underneath the summer bag, depending on the temperature of baby's room.  The Sleep Store has a range of lightweight, summer sleep sacks, including ultra-cool, breathable muslin bags, 0.2 and 0.5 Tog organic cotton bags and merino bags.  Merino is great for wicking away moisture and helps to regulate baby's temperature.  Our favourite summer bags include Woolbabe, Ergopouch Sheeting Bags and the gorgeous Little Unicorn muslin bags. Read more about choosing the best summer sleeping bag.