I think this year is the worst I have ever experienced for this phenomenon: One day 95, next day 65. And this fall is bizarro! Lots of fluctuating temperatures hour by hour.
So here's my day: I dress for the high temperature and then alternately shiver or roast, depending on what curve balls the weather throws me. How to dress for this? It's nuts.
Here's the secret: Layer. Wear a 3/4 sleeve light cardigan over a cami or tank that can stand on its own if need be. Opt for capris, with a little more coverage, instead of summery skirts or shorts. The barest, strappiest summer sandals look off now, so opt for ballet flats or a more substantial sandal that looks good with longer pants. (I'm loving this Attention women's stretch sandal, or this Jaclyn Smith nude sandal. There are even cropped pants that roll up or down as you need.
Probably the most important? Figure out if you'd rather be a little warm or a little cold, and dress accordingly. I hate being hot, so I'd rather under-dress.
I just stick with the same jeans and tshirt and maybe switch it to a tank top or shorts. but basically the same style. In nh when it gets cold, it will be cold! lol so thats more sweatshirts and thermal underwear then anything