Why Do We See Lightning Before We Hear Thunder?

Lightning reaches our eyes before thunder reaches our ears because light travels faster than sound.

lightning and thunder

Light travels at the rate of 186,282 miles per second, while sound is much slower, 1,087 feet, or about 1/5 of a mile, per second.

You can tell how far away a storm is by counting the seconds between the lightning flash and the clap of thunder, every 5 seconds between the two equals one mile!