People working in the communications field are generally required to be ‘smart casual’ in their dress. It is a good idea to mirror those working around you.
Take care to dress fairly conservatively and sensibly on your first day. It is always easier to take off a jacket and tie, or tone down the make-up and the heels, rather than turn up in jeans.
It is always a good idea for women to carry a shawl. This can work for warmth, or for a head cover if necessary.