There are a number of sites that offer five day forecasts for the area, interestingly they all seem to have different views about the weather ahead - three links are provided below, the first provided by the BBC for Perpignan, next Yahoo for Perpignan and the third by France Meteo from the Port Vendres weather centre (France Meteo have started charging for four day forecasts so this link just gives a two day outlook).

For a wealth of information on weather in respect of historical data visit Weather Underground.