Hoodies!
Hoodies are a great choice for when it's cold outside. They are very comfortable, and you can find ones with great Christian designs on them too! Just check the internet.
But what's extremely wonderful about them is they are loose so you don't have to worry about showing too much curve, and they are usually long enough so that you don't have to worry about "I see London, I see France."
They go great with a pair of jeans, sweats, shorts, or kapris. You can easily wear a tee shirt underneath in case you get too warm. For modest, casual dress, the hooded sweatshirt is where it's at.