anavguy, maybe this will help...
I coloured in the "inside" of the chart - it's supposed to show the envelope you are allowed to operate the CRJ in - so if you are not "inside" the envelope - in the orange area in the one I just made - you are outside of the "design envelope" for the aircraft. Which means maybe - not for certain, but maybe - some stuff won't work as designed.
The envelope is chosen to try to cover MOST eventualities - usually it won't restrict you. But if it happens to be very hot or very cold one day, you might not be legally permitted to operate the CRJ.
The easiest example is actually at sea level - you have to be at or above -40C, and not above 50C. Outside that range, no-go.