UPDATED 07/06/12 10:38 a.m.

CHICAGO (CBS) — Three people were killed, and seven others were injured, in shootings during the day Thursday as the high climbed to 102 degrees, and during the steamy night afterward.

The first deadly shooting happened around 4:10 p.m. in the 1300 block of West 48th Street, in the Back of the Yards neighborhood.

Sergio Garcia, 20, 4700 block of South Ada Street, was killed when he was shot in the right side and left buttocks, officials said. He was pronounced dead at 4:42 p.m. at Stroger Hospital of Cook County, according to the Cook County Medical Examiner’s office.

A second man, also 20, was injured in the shooting. He was reported in stable condition at Mount Sinai Hospital.

About 20 minutes later, an 18-year-old man was shot and killed in the 4800 block of South Hamlin Avenue, in the Archer Heights neighborhood, police said.

The victim was identified as Ricardo Alcantara, of the 6200 block of South Richmond Street, and he was dead at the scene, according to the Cook County Medical Examiner’s office. Further details of the shooting were not immediately learned.

In a third incident, Zachary Barrios, 18, was shot and killed in the 10600 block of South Champlain Avenue in the Roseland neighborhood.

Barrios, of the 9700 block of South Albany Avenue, was pronounced dead at the scene, according to the Cook County Medical Examiner’s office.

Further details of the shooting were not immediately available.

Among the seven injured in separate shootings was a 15-year-old boy shot in Englewood.

The boy was shot in the abdomen at about 5:50 p.m. in the 1600 block of West 60th Street, police said. He was taken in critical condition to Stroger Hospital.

A 48-year-old woman was also the victim of a shooting in the West Humboldt Park neighborhood. She was shot in the 4400 block of West North Avenue around 6:35 p.m., and was taken to St. Mary of Nazareth Hospital in stable condition, police said.

In an earlier incident, three men were wounded in a shooting in the Roseland neighborhood. A 19-year-old man was shot in the calf, a 34-year-old man in the back, and a 24-year-old man in the thigh in the 11300 block of South Wentworth Avenue, police said.

And in the morning around 7:50 a.m., a man was shot and wounded in the groin in a suspected drive-by shooting in 7600 block of South Greenwood Avenue in the Grand Crossing neighborhood. He was reported in serious condition at Advocate Christ Medical Center in Oak Lawn, police said.

The Sun-Times Media Wire contributed to this report.