I've done this for my adult child and am currently doing it for my other 3. But around ages 3 or 4 is a good time to start teaching kids about clothes for different weather. At this age, they can start choosing some of their own outfits.
First, show them we wear shorts and t-shirts when it's hot outside, like at the beach with Moana. But when it's cold out, we wear pants and sweaters. You can make it a fun game - "Is it a shorts day or a pants day today?" Let them look outside to help decide.
When they're 4 or 5, they'll understand a little more. Explain that we bundle up in winter to stay warm and healthy. Talk about materials like wool that trap heat. Show them light jackets for fall and extra layers for very cold days.
The key is making it interactive and letting them pick out clothes. Praise them when they choose correctly. If they're wrong, gently explain and guide them.
Keep adding more lessons each year. By 6 or 7 they should understand what to wear for the weather. But always double check before they go out - safety first! Be patient and make it an informative experience.
The earlier you start, the more they'll learn. But take it step-by-step. With your guidance, they'll be able to dress appropriately for the weather themselves in no time! Let me know if you need anything explained more simply.