How old does a baby have to be to be able to ride in the car and have the windows all the way down?

When the wind is coming at their face and they can either move their head out of the way or having the air blowing at them doesn't take their breath away. Babies hold their breath when air is blown at them (adults do as well to varying degrees). So, think about it, if you had a small baby, with air constantly blowing in their face and they couldnt' move away from it and it made them hold their breath, what do you think would happen? This can also occur in a stroller, carrier, etc.

I'm always very careful to check that my kids aren't getting too much air in their face that they can't handle, until they're about 2+ years old.

Just remember to much air can give them a stomach ache. My sister's baby had it happen to her and was in lots of pain! I think it has to do with swallow air or something. I could be wrong though! My son is a month old april 1st and I just have the front windows in the car open half way.

Wow, my son is now 6 months old and we dont put the windows down more then halfway in the front yet, i asked his doctor yesterday about it, he said during the summer, if its warm enough, the windows being all the way down is fine