The Warm Doublet is a piece of armor found in Breath of the Wild. It is one of the first pieces of clothing that Link can find along his quest, and will protect him from areas of mild cold, such as Mount Hylia. It has a base defense of 1 and cannot be enhanced.
When Link visits the Woodcutter's House on the Great Plateau, he will find The Old Man's Diary. Here the Old Man talks about a recipe for Spicy Meat and Seafood Fry, knowing that it includes Raw Meat and a Spicy Pepper. However, the Old Man has forgotten the third ingredient. He writes that if anybody can find the last ingredient and let him know, he will reward them with the Warm Doublet. The final ingredient is a Hyrule Bass, and when Link cooks it alongside Raw Meat and Spicy Pepper, he will cook the Spicy Meat and Seafood Fry. After showing the meal to the Old Man, he will give him the Warm Doublet.
If Link does not get the Warm Doublet from the Old Man at the Woodcutter's House, he can still get it from the Old Man, by ascending to the top of Mount Hylia. This area is cold, so it is recommended that Link cook some Spicy Peppers, to create some Spicy Sautéed Peppers, which will give Link low-level cold resistance.
After Link has completed all four of the Shrines on the Great Plateau, the Old Man will no longer appear on Mount Hylia, or at the Woodcutter's House. However, a Treasure Chest will now appear at the Woodcutter's House that contains the Warm Doublet.
Later in the quest, the Warm Doublet can be purchased at Ventest Clothing Boutique in Hateno Village for 80 Rupees.
The Warm Doublet is the first cold-resistant armor item available in the game, though its function deprecates once other enhanceable alternatives are found, like the Snowquill Set and the Ruby Circlet. It's also the only armor item with special properties available in the Great Plateau.
