BBC Weather is best but you could seek
http://www.wunderground.com/global/SP.html.
It is difficult to be in beach after September for some years there will be some sunny and pleasant days in October, but by the end of the October or beginning of November the temperature is over 15 degree Celsius, if you are lucky. Our ‘All saints’ tradition will eat panellets (kind of almond cookies) and roast chestnuts at the fireplace but at the present time very few people have a fireplace to light, but perhaps have our central heather on by this time of the year. Incase 1st November is not cold it is considered very strange. Naturally every one can enjoy a nice walk along a deserted beach, with proper wear of sweater, or even a windbreaker (the region is famous for the strong winds). It may be pleasant to be there without the hordes of tourists.