Funeral is a sad event, so you should represent your sorrow with appropriate clothing. Within our culture, the atmosphere is serious and gloomy. Funeral clothes should be in line with it. So, choose black or dark colours and do not overdo it with accessories.
Women should not wear short skirts, tops revealing shoulders and should consider decent make-up and jewellery. Wear rather more traditional clothing than sports bits.
Keep in mind that the choice of clothes represents your respect to the deceased, so adapt your clothing if he / she had any special requirements. The wishes of the deceased and his / her family have the highest priority.