So there is a huge difference between autism meltdowns and typical temper tantrums. Typically a temper tantrum is an emotional experience that happens when a child is unable to get something off they want desire, this could be a treat or a toy or their own way in a certain situation.

This negative backlash from not being able to carry out their own way causes them to rebel and create a tantrum to get rid of the anger and frustration the child is experiencing from that situation.

With an autism meltdown the person who is experiencing this situation is doing so because they are experiencing an overwhelming overstimulated environment.

could be a sensory processing issue or a change in routine of some other Autism related issue that is causing the person on the autism spectrum a lot of distress at that moment in time.

The meltdown occurs because the autistic person is finding it difficult to really their emotions and feelings to the situation at hand and end up having an outburst in the fun of an awesome meltdown, which is very distressing for the person.