Temper Tantrums can start as early as age 1 year old in some babies.
But it can vary as it depends on the toddler who is having the temper tantrum.
Some toddlers don't start to have temper tantrums until age 2 hence the name terrible two's but like I said above the temper tantrums can begin as early as age 1 so be prepared to deal with temper tantrums a year after your baby is born.
One of my kids started having temper tantrums at age 1 and the other kid never had a temper tantrum until age 2 years old so it can certainly vary from kid to kid.
Once the temper tantrums start they can continue until around 4 or even 5 years of age.
My 5 year old would have a temper tantrum in the store when he couldn't get what he wanted and I would then spank him in the store right in front of people and he would quickly straighten up and stop acting up.