Weather will likely play an important role when you plan your trip to La Seyne-sur-Mer, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually July and August, with an average temperature of 23°C, while the coldest months are January and February, with an average of 10°C. Average annual precipitation for La Seyne-sur-Mer is 788 mm.