LOS ANGELES — Hot summer days are, by definition, five weeks away. Consider Saturday’s “Pups at the Park” promotion on a hot night at Dodger Stadium as a teaser, then.

If the baseballs keep flying like they have since the return of the East Coast Dodgers, the low-scoring running environment of the early weeks of the season will soon be over. The Dodgers’ hold on the top spot could follow.

Julio Urías has become the latest Dodgers pitcher with no answers for Bryce Harper and the Philadelphia Phillies. Harper hit one of five home runs — four by Philadelphia — in the Dodgers’ 8-3 loss in front of a reported crowd of 50,279.

The Dodgers (20-12) have lost four straight for the first time since June of last year. Unlike the first three losses, there was no comeback at the end of the inning on Saturday. Cody Bellinger drove in a pair of runs with a double in the fourth inning and the Dodgers didn’t collect another hit.

Mookie Betts homered in the first inning against Ranger Suarez (4-1), who allowed five hits and three runs through seven innings. He walked one and struck out six.

Like Tyler Anderson and Walker Buehler before him on the show, Urías struggled to push Harper away. The longtime Dodgers foe went 3 for 4 (one double, one home run, one bunt single) and three RBIs. He’s 8 for 12 with a home run in every game of the series.

Jean Segura, Kyle Schwarber and Rhys Hoskins also homered against Urías (2-3). The southpaw had never allowed four home runs, six extra hits or eight runs in a game. The Phillies had it all after four innings.

In the first, Harper pushed a well-located curveball off the end of his bat into shallow left field. Because the Dodgers were moved in the opposite direction, Harper was able to pull out a brace.

The next batter, Nick Castellanos, grounded to the third base line. Justin Turner gloved the ball on his backhand but threw a jump to first base that Freddie Freeman couldn’t get off the ground. Castellanos was safe on the error, so the round continued for Segura.

Segura didn’t make hard contact with Urías’ curveball 1&1, but his fly ball found the shallowest corner of Dodger Stadium: the corner of left field. At 91.0 mph by Statcast, it was the second-smoothest home run this season. Due to Turner’s error, the three points were not earned.

The third leg was not so favorable to the ERA of Urías. Rhys Hoskins chose. Alec Bohm doubled. Harper cleared the bases with his ninth homer of the season, a 420-foot parabola. Philadelphia led 6-1.

Homers from Schwarber and Hoskins in the fourth inning extended the lead to 8-1. Urías was never in danger of being fired. No relief pitcher started warming up until Reyes Moronta in the sixth.

Therein lies the vicious circle of frustration for the Dodgers in the series. Each of their starting pitchers has been uncharacteristically bad. Tyler Anderson gave up seven runs on Thursday. Walker Buehler allowed five on Friday. Urías awarded eight.

But the bullpen wasn’t a safe bet either. Daniel Hudson suffered his second loss in as many days on Thursday. Brusdar Graterol gave up three runs in the 10th inning Friday.

With 22 games to play over the next 22 days and their five-man rotation reduced to four in light of Clayton Kershaw’s latest injury, manager Dave Roberts has been forced to extend his starters regardless of the scoreboard. Against Harper and the Phillies, it’s a tough place to be.

“We have to find a way to get it out,” Roberts said.