Well here in England I think wet earth. The trouble is that it smells like this all the year round.
Seriously, I have often thought that my seasonal greetings do not fit properly in the southern hemisphere. Except for a curious fact. Having been born in Argentina I can tell you that our Christmas cards also feature snow and elks, both unknown there. Unless you go very south, for the snow, that is. You find elks only in zoos.
My brain goes into children’s book illustrations mode when I think about the seasons. Sandcastles, hammocks, cocktails, sunglasses, bikinis. But in reality, smells are more pertinent. Freshly cut grass, after sun, petrichor. Barbecue, melon, sweat.