Henkyou Gurashi no Maou, Tensei shite Saikyou no Majutsushi ni naru - Ch. 44 - Yuuki and Odette, Reporting to the [Adventurer Guild]

[frostmonolith]

She double layers it with a nightgown. Isn't that uncomfortable? You either wear 1 or the other.

It might be for warmth, or it's just how she likes it. There's not much information about the weather being explicitly mentioned so there could be various reasons if it isn't as simple as warmth.