The fourth season of the BKT United Rugby Championship kicks off tonight, with eight-time winners Leinster the first of the Irish sides in action as they travel to Edinburgh.There is an opening-round Irish derby on the card tomorrow as Munster, along with Leinster beaten semi-finalists last season, entertaining Connacht at Thomond Park.The final game of the round sees defending champions Glasgow take the short hop to Belfast where Ulster are the hosts. ONLINE We'll have live updates, live scoring, reports and reaction from all three games on rte.ie/sport. TV You can watch live coverage of Munster v Connacht (Saturday 5.30pm) on RTÉ2 and RTÉ Player.Edinburgh v Leinster (Friday 7.35pm) is on TG4 and Premier Sports, while Ulster v Glasgow (Saturday 7.45pm) is live on Premier Sports.All games are also shown live on URC.tv. RADIO There is live commentary on Munster v Connacht on RTÉ Radio 1's Saturday Sport with Neil Treacy and Mike Sherry. WEATHER There are light clouds and a gentle breeze expected for Leinster's game in Edinburgh on Friday night, amid temperatures of around 13C.Limerick expects partly cloudy conditions in about 17C for the derby, while Belfast is set for sunny weather around kick-off with similar temperatures. Listen to the RTÉ Rugby podcast on Apple Podcasts, Spotify or wherever you get your podcasts. Leo Cullen's side welcome back Jamison Gibson-Park after a hamstring injury, while Cian Healy is set to earn a record-equalling 280th appearance if called upon from the benchProp Rabah Slimani in line for his debut and hooker Gus McCarthy gets his first Leinster start.Sam Prendergast, who will miss the next three rounds as he goes on the Emerging Ireland tour, gets the nod at out-half.Leinster have lost their