Dressing at fifteen degrees
Short answer: One layer and something to take off. Fifteen degrees is pleasant in the sun and cool in the shade, and the difference is bigger than the number suggests.
Sun and shade
In direct sun, fifteen degrees feels like twenty. In shade and wind it feels like ten. That is why a layer you can remove matters more than what you start in.
The simple solution
A t-shirt and a thin jumper or shirt you can tie round your waist. Bamboo viscose feels cool against the skin in sun and warm enough in shade. See bamboo t-shirts for men.
In the evening
Fifteen degrees at five o'clock is ten degrees at nine. Take an extra layer if you will be out in the evening. See bamboo clothing for women and bamboo sweatshirts for women.
Frequently asked questions
Can you wear shorts
Yes, in the sun. In the shade most people get cold legs.
Is fifteen degrees t-shirt weather
In the sun yes. Always bring something for when the sun goes down.
What about socks
Thin bamboo socks are comfortable. Bare feet in shoes get clammy.