What clothing size is your baby wearing?

My daughter just turned 2 months old yesterday and she's about to be in 6 month sizes! She's average height and weight and she's still in size 1 diapers. All of the 6 month clothing she already has is meant for May weather, so now I have to return all of it and get her winter 6 month clothes which is really annoying. Is this happening to everyone else? Clothing sizes seem to be really inaccurate and now I don't know how to buy her clothes ahead of time..