She was definately under-dressed to be out for an extended time in the evening and was probably extremely cold with the additional wind riding her bicycle. So I doubt she was riding around the neighborhood maybe making a stop at the Kwik Trip for a snack or something as opposed to going straight home. As someone that lives just across the border in the Twin Cities, there's some points to be made.
First, we don't know what time she actually left, and in the spring and fall there are typically wild temperature swings between the day and night. She probably rode down doing the day when it was warmer and maybe didn't think ahead about how it would be colder in the evening.
Second, it's common to deliberately under-dress a bit if you know you're not going to be out in the cold long and are going to someplace warm. When it's below freezing out, yes I put on thermal underwear, parka, gloves, and hat if I'm going ice skating. If I'm going to the store I'll just put on a light weather jacket rather than deal with the time and discomfort of being all bundled up. Just a hoody for a 10 minute bicycle ride home doesn't seem that odd of a choice to me.
