Did your mother tell you to make sure to layer up
Layered clothing is a term describing a way
of dressing using many garments that are worn on top of each other.
Some of the layers have different, largely non-overlapping, functions.
Using more or fewer layers, or replacing one layer but not others,
allows for flexible clothing to match the needs of each situation. Two
thin layers can be warmer yet lighter than one thick layer, because the
air trapped between layers serves as thermal insulation. Layered
clothing is particularly relevant in cold climates, where clothing must
at the same time transfer moisture (wicking),
provide warmth, and protect from wind and rain.
Outdoor and sportswear manufacturers favor layered
clothing because, among other reasons, it allows them to offer so-called
"technical" or "functional" clothes which are optimized for the
particular demands of a specific layer. Such clothes are often made of
advanced synthetic materials, and can be expensive.
Another benefit to wearing multiple layers of
clothing is that if you become too warm, you can reduce layers as
Put on a t-shirt, then a thin sweatshirt, then put
on a sweater, then put on a hoodie. Now you are layered.