Key Facts

• About 200 million people in the U.S. face extreme heat alerts.
• The alerts are in effect on Wednesday.
• The extreme heat is expected just before the Fourth of July.
• These alerts warn people about dangerous high temperatures.
• The forecast and updates are provided by meteorologist Rob Marciano.
• The extreme heat can increase health risks like heat exhaustion or heat stroke.
• People are advised to stay hydrated and avoid outdoor activities when possible.