Excessive heat delays high school graduation in New Jersey. This is what schools are concerned about.

CLIFTON, NJ — Extreme heat creates dangerous conditions in New Jersey and delays at least one high school graduation.

Clifton High School has announced that Thursday’s graduation ceremony will be postponed from 3:00 PM to 7:00 PM due to the oppressive weather.

Other counties affected by the sweltering temperatures include East Orange, Old Bridge and Perth Amboy. They called for a half-day or early dismissal on Thursday so that students and staff can avoid peak hours.

Schools across the state have been adjusting their schedules all week in response to the heat.

View the first warning forecast here.

In Ridgewood, leaders imposed a voluntary water restriction, asking residents not to water their lawns until the end of the week.

Officials warned that excessive water use has already caused water tanks to reach dangerously low levels. If the tanks are not refilled, the city may have to stop using all sprinkler systems.

What is a heat advisory?

The National Weather Service issues a heat advisory when the heat index is forecast to rise between 95 and 99 degrees for at least two days in a row. A heat advisory will also be issued when the heat index is expected to rise between 100 and 104 degrees.

What is an Excessive Heat Warning?

The National Weather Service issues extreme heat warnings 24 hours before a forecast heat index of at least 105 degrees for at least two consecutive hours. Although not always the case, excessive heat warnings usually coincide with heat waves.

Symptoms of heat stroke

Sunstroke is the most serious heat-related illness and can lead to disability or death. When someone experiences heat stroke, their body temperature can rise to 106 degrees or higher within 10 to 15 minutes and they stop producing sweat, according to the Centers for Disease Control and Prevention.

Symptoms include:

• Hot, dry skin
• Confusion, hallucinations or disorientation
• Loss of consciousness or unresponsiveness
• Nausea or vomiting
• Problems breathing
• Rapid, powerful pulse
• Weakness
• Dizziness

More summer safety tips can be found here.