Even though it spring, it's still a bit cold. However, I see some people wearing lesser amount of clothing's.

That or they didn't realize how cold it was outside. I used to do that and then I'd be cold all day. I went out yesterday in a long sleeve shirt and carried my jacket along. And I did need it.

Nah, it's just one's own subjective perfection of cold and warm. For me this is nearly short sleeves weather. Then you have people like my upstairs neighbor who'll be wearing a hoodie in late August with like 24°C at night.

Lol... It's not that cold now... even I'm going outside barefoot.