Wait until your baby sits up steadily and holds their head well while wearing a...

https://smoothdecorator.com/cold-weather-biking-what-should-your-baby-wear-in-a-bike-seat/

Wait until your baby sits up steadily and holds their head well while wearing a helmet, usually around 10 months. Front seats keep toddlers close, rear seats offer extra stability, and trailers work perfectly for naps