this is winter. You accepted Suna's invitation to go out at night, you thought this would just be an ordinary nightride so you only wore your daily clothes, namely short jeans, shirt and a cardigan that wasn't too thick and warm.

While on the trip you felt cold but you didn't admit it, until.

Suna: what happend?

while driving, Suna noticed you were shivering, but he tried to tease you because he was wearing his warm jacket.