Cynthia Marie Randolph, 25, was jailed on Monday for 20 years

A Texas mother who locked her two children in a car on a boiling day to 'teach them a lesson' has been jailed for their deaths.

Cynthia Marie Randolph, 25, left her one-year-old son Cavanaugh and two-year-old daughter Juliet in her 2010 Honda Crosstour for several hours on May 26 last year.

The toddlers had refused to get out of the vehicle at the family's home in Weatherford, Texas, and Randolph decided to leave them in there to 'teach them a lesson'.

She went into the home, smoked marijuana and fell asleep, leaving the toddlers outside in the vehicle as temperatures soared to 96 degrees.

Cavanaugh, one, and Juliet, two both died from heatstroke after being left in the car for two hours

By the time she woke up, the children had died in the vehicle.

At first, she called 911 and fabricated a story that they had vanished from the house while she folded the laundry and locked themselves in the car 'for no more than an hour' before she found them.

To make it look like an accident, Randolph smashed the car window to get them out.

Later, she admitted leaving them in there on purpose.

She believed that Juliet would be able to let herself out and bring her brother with her so she went into the home, watched Keeping Up With The Kardashians, smoked marijuana then took a two-to-three hour nap.

Randolph was arrested and charged with two second-degree felony counts of recklessly causing injury to a child.

Randolph, 25, left the children in the car then went into her home to watch Keeping Up With the Kardashians, smoke marijuana and take a two-hour nap

By the time the mother-of-two woke up again, the children were both unresponsive. She lied to police at first by claiming they had wandered off as she folded laundry inside

She was convicted this week and given the maximum 20 year sentence for each.

The judge ordered her to serve them simultaneously.

The children's official cause of death was heatstroke.

They had perished in the car for two hours by the time their mother got them out.