Why do kids insist on wearing summer clothes in winter???

It's 38 degrees in Denver and my 6yo daughter is convinced she needs to wear her sandals and shorts. Every. Single. Morning. We have this battle before school. I'm not trying to helicopter parent but also I don't want her getting sick? But maybe I'm being paranoid. Do other people's kids actually listen about weather-appropriate clothing or is this just a phase I gotta ride out?