Air carrier pilot reported their weather radar failed. Due to known weather along their route they returned to their departure airport and made an overweight landing.

Narrative

Flight from ZZZ to ZZZZ. There was a large area of weather over [area] while the weather on the northern operation of the route was relatively clear. The logbook had multiple previous radar write ups with the most recent signed of on Date. When we got to cruise I turned on the radar and it failed. We tried cycling the off/on a number of times but it failed repeatedly. I noted that the WSI app showed we could keep clear of the weather by taking a more easterly route down the coast. I requested that route from ATC and asked the dispatcher to look at it and see if he thought we could stay clear of the weather on the new route. He was concerned about a segment of the route that had embedded thunderstorms so we elected to return to ZZZ for maintenance. We [requested priority handling] with Center and landed overweight. It was an uneventful approach and landing with a soft touchdown at 156;800 lbs. I wrote up the radar and overweight landing. We changed aircraft and proceeded to ZZZZ.I have high confidence in Maintenance. On this occasion the radar tested okay on the ground but failed airborne. I'm not sure what the technical issue was with the radar so I can't comment.