Summer Grant, seven, died when the bouncy castle she was on was sent “cartwheeling” 300 metres down a hill next to an Easter fair in Harlow, Essex.
William Thurston, 29, and Shelby Thurston, 26, were both found guilty of manslaughter by negligence, and of a health and safety offence.
Sentencing, Mr Justice Graham said the married couple had taken the most “monumental risk with children’s lives by continuing to allow children on the bouncy castle”.
“That risk-taking cost Summer her life,” he said.
He called on health and safety experts to make it compulsory for fairground operators to have proper wind speed measuring equipment, calling it “extraordinary” that it should be commonplace not to.
A yellow weather warning had been in place on the day of the incident, which took place two days before storm Katie hit Britain in March 2016.
Prosecutors had argued the bouncy castle had not been adequately anchored to the ground and the defendants had failed to monitor weather conditions to ensure it was safe.
The instruction manual for the inflatable was destroyed a year before the incident in a fire, the court heard.
Onlookers said they saw the bouncy castle “rolling” down the hill after being lifted 30 to 50ft in the air, over a caravan and into a field.
Summer’s mother Cara Blackie said she had screamed when she heard that her daughter had died, and now suffers from debilitating anxiety and depression. She was unable to read her full statement at the hearing.
“I never thought that my Summer playing and having fun on the bouncy castle would end her young life,” she said.
The girl’s father, Lee Grant, said he heard a scream and turned to see the bouncy castle in the air.
He attempted to give chase but could do nothing.
Summer was rescued from the bouncy castle but she died from her injuries in hospital.
“When Summer died, I felt as if I died too,” he said.
“I felt as if I had nothing left to live for because she was my beautiful angel.”