We already know that a large part of the East is on the threshold of a heat wave that will persist through at least midweek. The Southwest has already turned into an inferno like it normally does this time of year. However, from about Salt Lake City northward, it's not too bad right now, and it's actually pretty cool in Washington, northern Idaho and Montana.

July is king of hot weather, though, and soon even the Northwest and northern Rockies will be in the cooker. That part of the country can expect temperatures to turn sharply upward Tuesday then it will become downright hot during the middle of the week with 90s showing up in a lot of places.

Story by AccuWeather.com Senior Meteorologist John Kocet.