Although there is no specific dress code for Wimbledon goers, smart dress is encouraged. It is also advised that you consider all weather conditions when going to Wimbledon - after all, this is Great Britain! For women, a light jacket to wear over your summer dress is a good idea, as are sunglasses.
In short, there is no specific dress code for Wimbledon although fans attending the All England Club are often encouraged to dress smartly. The only official rules on the Wimbledon website regarding entry to the grounds state that no offensive or political messages can be displayed on clothing.