The jean is a casual dress and it can wear on any situation and season. But if you feel more cold keep the dress that you feel more comfort.
You could take a pair with you if it's cold, but it rarely is this time of the year. I'd stick to sorts, or dresses and skirts (if you're a girl) if you wear jeans every day there you will be so sweaty. It's usually super hot there
I dunno if you live there or are visiting, but anyway... if you live there then see how the weather feels on that day, and if you are visiting, take a pair with you and see how the weather feels.
