Clothes against hot weather

According to my a source here they do indeed exist and the parts or quests you need to complete are all surrounding the volcano to start off:

Step 1

The first thing you need to do is head to Foothill Stable, south of the giant volcano in the north-east. You’ll see a girl with a broom in front of the stable. Her name is Gaile. Talk to her, and buy 3 Fireproof Elixirs. You’ll need 150 rupees.

Step 2

Take the road north, into the Eldin region. Follow it until you pass a wooden bridge across a lava stream. This part is called Southern Goron Mine. As soon as you’re off the bridge, look to your left. You should see a weary traveler called Kima. She’ll offer you the Flamebreaker armor in exchange for 10 Fireproof Lizards.

Step 3

They’re not hard to find, but they spook easily, so you’ll have to sneak up on them. Look around the area between the two bridges. If you catch all the ones that roam freely and still don’t have enough, you can lift rocks and find them under. Just keep in mind you need to press the grab button as soon as you start lifting the rock, or else the lizard will escape.

Step 4

Once you’ve got 10, talk to Kima again, and she’ll give you the suit. If you want the helmet and trousers, you’ll have to visit Goron City farther up the road. Go to the armor store there and you’ll see them on display. The Flamebreaker Boots cost 700 rupees, while the Flamebreaker Helmet is a whooping 2000.

I don't know the stats that the suit holds only that they are fire resistant.

Another suit ( That Link doesn't like ) is a free womans suit in gerudo town. The tutorial can be found here.

Comment by Gwelin

According to a comment by Gwelin there is a difference between heat and fire protection armour:

The environmental conditions between Gerudo Desert and Death Mountain are different—Heat for the former, and Fire for the latter. Protection from Fire will not help in extreme heat, and protection from Heat will not keep Link from bursting in to flames.

The most effective Heat Resistant Armor I've found is the Male Gerudo Armor set (Desert Voe) that is sold in the Gerudo City Secret Shop.

Unlike the Female Gerudo Armor set, it has some actual defense to it, and can be upgraded with monster materials. Additionally, it's heat resistant is per-piece instead of a set bonus, so if you only need 1 level of heat protection, you can only equip the Head piece or Leg piece (allowing you to keep wearing the Champion's Tunic, for instance).

In addition to the other answers here, regarding armor, be advised that you can also equip a weapon that emanates cold energy to ward off the heat. A Frostspear or similar, while strapped to Link's back, will chill him out a little bit and provide that little extra edge to ward off the most extreme head.

(The same is true in reverse for weapons like the Flameblade in cold weather.)