A319 Captain reported heavy weather during climb. After encountering heavy hail; the First Officer's wind screen shattered. The flight crew performed an air turn back to the departure airport.

Narrative

Aircraft X departed from ZZZ Gate x at XA00L. After some significant taxi delays; Aircraft X; with 115 SOB; finally lifted off from Runway XXL at XA42Z and was turned South toward ZZZZZ intersection. South of ZZZ was a rapidly developing line of weather running on an East-West line. Using our weather radar; we were able to discern several embedded cells with multiple small areas of green (light) precipitation between; and those were the areas the preceding aircraft were utilizing to navigate through the line. The First Officer (FO); as flying pilot; initiated a discussion about a left turn to avoid penetrating the weather; but due to proximity; the thin nature of the line; and gaps between severe cells it was decided to continue. Just before entering the clouds we observed lightning on both sides of the aircraft and ATC issued a report to us of severe turbulence reported on our track at FL230 and; since we were much lower; we reduced our rate of climb in an attempt to avoid the turbulence. We were flying an assigned airspeed of 250 kts. Aircraft X; approx 5 miles in trail of a preceding aircraft; then penetrated the weather and encountered moderate to severe turbulence at approx FL180. Unreported heavy hail was encountered almost immediately and lasted 10-15 seconds; during which time the First Officer's windscreen was impacted with sufficient force to shatter the outer pane of the window. An immediate ECAM was also generated for failure of the right windshield anti-ice heating element. After another 15-30 seconds the aircraft was clear of all rain and clouds. Out of concern for the integrity of the remaining inner pane of the windscreen; Aircraft X [requested priority handling] with ATC; stopped our climb; asked for vectors around the weather back to ZZZ; and descended back down to 17000 ft. (to limit the force of aircraft pressurization on the broken window). Aircraft speed was limited to 250 kts. maximum by the crew to further minimize aerodynamic pressure on the remaining window pane. ATC vectored Aircraft X to the East approximately 100 NM in order to circumnavigate the weather. The Flight Attendants were briefed on the situation and information was discussed; and the Captain announced the general nature of the aircraft condition along with the plan to return to ZZZ in a PA to the passengers. After establishing on eastbound vectors; the Captain notified Dispatch of the aircraft state and intentions. A brief discussion regarding a divert to ZZZ1 was held over ACARS; but the crew felt best with a return to ZZZ remaining clear of all weather and Dispatch did not disagree. The aircraft was able to turn to the North just East of the ZZZ2 navaid. Shortly thereafter the aircraft was able to turn West toward ZZZ and remain clear of weather while returning for landing. We flew direct ZZZZZ1 then direct ZZZ and eventually were given vectors to a medium final to the ILS XXC. Due to a distorted forward view from the right control seat due to the various fracture lines in the window; the crew opted to transfer control to the left seat for landing at ZZZ. The landing; rollout; and taxi in were uneventful. The aircraft parked at y at XB14L. Maintenance action items were submitted for the broken windscreen and the related malfunction of the right windshield anti-ice heating element. After block-in at the gate; personnel from several stakeholder organizations within the company came to the aircraft; took photos; and asked a few simple questions. The Captain and FO spoke with a pilot retiree on the flight deck. The Captain contacted the duty Chief Pilot; providing all requested information and discussed the well-being of the crew. The Captain was then contacted by another Captain and conducted a short interview. The flight deck and inflight crews both felt comfortable swapping into another aircraft and continuing on to ZZZ3. Aircraft Y (second attempt) released brakes at XC38L and arrived at the gate in ZZZ3 at 0XD43L with XXX SOB; fora total block time of 2:05.