There are a couple of thing that could cause this. You could have a caliper or cylinder locked up or the emergency brake cable could be frozen up. It is best to have it looked at right away.
You may have driven the vehicle with the parking brake applied.
make sure it's not the rear brakes hanging up, see if they feel hot, if you have drum brakes on the back a wheel cylinder could be hanging up.
Back off the brake adjustment, or back off the e-brake adjustment, or the e-brake cables are stuck. No need to open bleeders.
Either your brakes are sticking or they are adjusted to much.
It most likely means that your brakes are very hot, and that some sort of liquid has touched your brake pads or rotors. Be careful about warping in the rotor.
Brakes are adjusted too tight. Brakes are misassembled. Brake hose is restricted, holdings the brake on.
The rear brake on that side may be locking up and getting extremely hot.
This could be for a few reasons, but if they are getting hot without you applying them, I would suggest that they are sticking and causing the pads to rub on the discs, or if they are drum brakes, the shoes on the drums. If they are only getting hot as a result of using the brakes, I would suggest checking that the brakes are balanced properly, and that the front brakes are not doing all of the work/ or that the back brakes are working at all.
Poor adjustment, excessive use, worn shoes and/or drums, bad slack adjuster and/or brake chamber (if equipped with air brakes).
Friction makes brakes get hot. Whenever you step on the brake pedal, the kinetic energy of the vehicle is converted to heat energy to stop the vehicle. Having said that, the brakes can run a little hot if the calipers are not fully releasing and the rear brakes can overheat if you fail to release the parking brake. It's extremely rare that the master cylinder doesn't fully release the brakes.
The brakes or rotors could be making the rear driver tire get hot on a 1995 Nissan hard body.
Weather doesn't matter. Have the brakes inspected asap before something happens.
There is a leak in the rear lines running to the back.