Put on your sun hat and herald the start of summer with these new stamps. A must-have for your holiday postcards! Cool down or get warm? The two new summer stamps show exactly what people like to do in the summer, according to an internal Swiss Post survey: swimming in a pool, lake or river to cool off, or lighting a barbecue and treating themselves and their loved ones to some culinary delights. Summer is just around the corner – can you feel it, too?