Applying colormap to a 2d area beneath a data plot line

I have a data plot of ambient temperature in a room, and have made an avi output of the temperature changing through-out 24 hours using getframe and movie2avi. Is it possible to apply a colormap to the 2 day area beneath the line, so (if using 'jet' colormap) the warmer temperature correlate to a redder colour, while lower temperatures are representned in blue?* *

Any help would be much appreciated, Cheers