Wait until your baby is one year old and holds their head steady while wearing...

https://papa-wiki.win/index.php/Is_it_Safe_to_Bike_with_a_Baby_in_the_Rain%3F_A_Mechanic%E2%80%99s_Guide_to_Wet-Weather_Commuting

Wait until your baby is one year old and holds their head steady while wearing a helmet. Strong necks are vital for safety. Choose front seats for easy bonding, rear seats for toddlers, or trailers for the lowest center of gravity