Agree with the others here , the temperature is a red herring . Brakes are designed to run VERY hot and ambient temperatures will only affect this to a very limited effect.
Is this just the fronts locking , or are the rears joining in as well? If the latter then I would look at other potential causes , but if it is just the fronts then a sticky pad would would appear to be the most likely culprit BUT it would be most unusual to have 2 (or 4 ?) such problems simultaneously, so I am trying to think a little broader. Have the pistons in the calipers become "sticky" and not retracting? Again it is very unlikely that there would be all 4 pistons affected, but just check them all.
Unless the car has been modified with a brake bias adjustment, the front/rear balance is set by the master cylinder, so nothing can easily be changed in that respect.
I am not sure if 1994 is the old style brakes (drums manually adjustable) or the new (rear shoes auto adjusted? If the former try manually adjusting the rears up until they show more "bite" , this may help give a bit more power to the rear brakes and thus decrease effort on the fronts.
This one is really puzzling me.
