Between 2am and 3am the woman was walking along Church Street when she was approached by a man who tried to engage in conversation with her. When the woman refused, he grabbed her before snatching her phone before making off.
The man is described as around 25 years old, slender and wearing a beige knitted top with the hood up and dark trousers.
PC Elliot Wright, investigating, said: “This unprovoked incident was a scary ordeal for the woman and such behaviour will not be tolerated. I would urge anyone who witnessed the incident or a man matching this description in the area to get in touch.”
Anyone with information is asked to contact PC Wright on 101, or call Crimestoppers anonymously on 0800 555 111.