Upvote:1
The National Weather Service is probably one of the best sources for this. They have lots of maps for both current conditions and forecast conditions. You can find their page for graphical forecast maps here:
http://graphical.weather.gov/sectors/conus.php
For example, here is what their graphical forecast looks like for temperatures at 5 PM EDT today:
The same page also has forecast maps for:
They also have a 'metric units' link you can click that displays a page showing you how the colors map to the appropriate metric unit scale, if you prefer Celcius, for example.
Weather Underground is also a good source. You can find their interactive temperature map here, though they're a private company so it would probably violate the copyright to post the image here. The data is freely available on their website, though.
Upvote:6
It would seem like weather.com has an interactive map that is at least partially useful.
http://www.weather.com/weather/map/interactive
Unfortunately, it only seems to provide you with data for a couple of hours, and, depending on the region, temperatures between the day and the night may or may not be similar. Also, it is limited in the way at which colours are represented, where you really have no clue whether it's 20 or 30 degrees C in a certain region.