Relentless heat wave reaching maximum strength: Weather updates

A historic heat wave reached its maximum intensity across the southwestern United States and California on Sunday and established numerous records well above 100 degrees. Death Valley, Calif., infamous for its heat, hit 128, setting a new daily record but fell short of 130, which would have matched the highest temperature observed worldwide in the past 90 years. Even as the heat is forecast to very slowly ease in the West during the workweek, it is expected to become more entrenched and expand over the south-central and southeastern United States, where tropical-like humidity is already producing dangerously high heat indexes. An earlier version of this article incorrectly said that, in Arizona, Phoenix tied or broke a calendar-day heat record for the fourth straight day. Phoenix tied or broke a calendar-day record for the third straight day. The article has been corrected. Our warming climate: In the Eastern U.S., the record-breaking heat wave is reaching is peaking. July was Earths hottest month , and heres where the worst, record-setting heat occurred . Use our tracker to see your citys extreme heat risk . Take a look at what extreme heat does to the human body . How to stay safe: Its better to prepare for extreme heat before youre in it. Heres our guide to bracing for a heat wave , tips for staying cool even if you dont have air conditioning , and what to know about animal safety during extreme heat . Traveling during a heat wave isnt ideal, but heres what to do if you are . Understanding the science: Sprawling zones of high pressure called heat domes fuel heat waves. Heres how they work . You can also read more about the link between weather disasters and climate change , and how leaders in the U.S. and Europe are responding to heat .