Under Texas law, when is it illegal to leave a child unattended in a vehicle?

Leaving a child unattended in a vehicle can pose serious dangers, particularly when temperatures rise. Under Texas law, it becomes illegal to leave a child unattended in a vehicle when the temperature is above 70 degrees Fahrenheit due to the significant risk of heat-related illnesses. Even a short period of time can lead to dangerously high temperatures inside a vehicle, creating life-threatening situations for children.

The other options, while they may describe risky situations, do not specify a legal threshold that fits within this context. Temperature is a direct factor impacting the safety of an unattended child, making it the critical element under Texas law.