This site contains current and historical (back to February 2000) satellite imagery from the polar-orbiting Terra and Aqua satellites. Flying at relatively low altitude, these satellites are able to provide very high-definition cloud, ocean, and land-based images of specific geographical regions. Because the satellite orbits as the Earth spins beneath it, there are gaps in coverage between successive satellite passes.
This page shows high and low temperatures (observed and departure from average) across the U.S. Unfortunately, the images are 36 to 48 hours old.
NCEP/CDC Temperature Maps
Site contains much weather information, including “departure from average temperature” maps. You’ll just have to do some clicking of the many links provided.