It's a bit tricky to talk about the "speed" of lightning when it zigzags, because it's not actually moving in a single, continuous direction.

Here's why:

* Lightning is a discharge of electricity: It's not a physical object traveling like a car.

* The zigzag shape is an illusion: The branching path of lightning is caused by the electricity seeking the path of least resistance through the air. It's not a single bolt moving back and forth.

* Speed varies: The speed of the electrical discharge can vary along the path, depending on the air density and other factors.

What we can say:

* The average speed of lightning: The initial "leader" stroke that creates the path is estimated to travel around 100,000 meters per second (about 300,000 miles per hour).

* The return stroke: This is the main discharge that we usually see as lightning, and it travels much faster, up to 1/3 the speed of light (about 100,000,000 meters per second or 220,000,000 miles per hour).

So, while the zigzags aren't a movement in a single direction, the electricity itself travels at incredible speeds within that branching path.