hot as blazes
Also, hot as hell. Extremely warm, as in It was hot as blazes in that room, or I'm hot as hell and would love a cold shower. The first of these hyperbolic similes dates from the mid-1800s, the second from the early 1900s.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.