A heat dome​ is trapping over 90 million Americans in extreme temperatures this week with the National Weather Service​ ...

Heat Wave Map Shows Zone Spread Into Five New States. Published May 25, ... The highest NWS heat warning is "extreme," shown on the map by the color purple, ...

Dull colors can result from drought and extreme, persistent heat because they put trees under more stress. Any spring or summer drought can stall the beginning of color.

The national map is color-coded to demonstrate heat risk from “none” to “extreme.” The weather service calculates how unusual the weather is for a given time of year, how long the heat ...