The Forecaster

 is a psychic child living under the bridge at 188 Trading Post in 2281.

Background
The Forecaster lost his parents a long time ago, and has been on his own since, but he's gotten used to it.

Other interactions
You can pay him 100 caps to "hear his thoughts" on "You", "Here", or "Everywhere". He is basically a fortune teller.

Bugs

 * On the PC Patch 1, the Forecaster can be seen floating in mid-air a few inches off the ground instead of on the ground in his sitting pose.
 * If you try to kill the forecaster with the sandman perk enough times, you may end up being transported to an irradiated part in the wasteland with no means of escape. (Confirmed for PS3)

Appearances
appears in Fallout: New Vegas.