I know you might like to have your showers hot when on your body but, it isn't what's always best for your hair for the entire washing process. I wanted to go over the list on what the hot and cold temperatures can do for your hair to give you a better reading on what temperature to use next.
If you want the simple formula of what you can do then under warm temperature water you can wash, detangle and condition the hair. However, when you want to get that final rinse before you get out the shower put it on cold water to be able to seal the cuticles.
Once you do the first shampoo with hot water if you're usually going for a second shampoo or simply rinsing then that can be at room temperature.
Rinse away the gunk
Hot water is great for rinsing away all the oil, product, build up and dirt that can get trapped on your scalp
Opens up pores
If you wash your hair in hot water too long, it can open up the pores and cuticles. Opening up the pores and cuticles of your hair can lead it to be being dry and brittle. If hot water is on your hair too long, it can strip your hair of its sebum (natural oils).
If you have color try to be careful about putting in too much hot water. What hot water can do is open up the cuticle that can fade your hair color more quickly.
It helps with retaining moisture that will keep moisture within your hair to help with detangling and girls your curls more definition.
Cold Water also helps with increasing the shine by having the cuticle sealed so your hair can have a smooth finish.
If you're not so much into volume cold water can help with reducing the amount of volume in your hair.