Always, always, always bring a sweater with you no matter what the temperature is outside or where you are going.
If you don’t need it and you have it anyway, you don’t need it.
If you do need it, and you don’t have it, you will be miserable for the rest of the time you are in a place.
My car is boiling hot, but the Starbucks I’ve been in for the last hour or so and plan to be in for the next forty or so minutes is freezing, and it just started getting cold.
There’s a reason Grandmas tell you to wear a sweater, and it’s not modesty.