Swedish police are warning that parked cars can quickly become life-threatening in warm weather, even with windows slightly open. Temperatures inside a vehicle can rise rapidly, creating a dangerous environment, particularly for children and pets. Authorities emphasize the speed at which this occurs, highlighting the potential for heatstroke and even death. The warning comes as temperatures are expected to increase across the country. Police advise vigilance and caution, urging individuals to never leave vulnerable individuals unattended in parked vehicles. They are utilizing graphics to illustrate the rapid temperature increase within cars.