Summer lasts from December to February and it's the best time to visit southern Patagonia, when days are long and sunshine is plentiful. Unfortunately, sometimes half the population of Buenos Aires seems to descend on popular towns like El Calafate in the summer, so it's worthwhile to consider a trip in the shoulder seasons of spring and fall, when prices are lower, attractions less crowded, and the weather slightly less cooperative. Many hotels and restaurants close in winter, but visitors intrepid enough to brave frigid temperatures are rewarded with blessed isolation, less wind, and awe-inspiring mountain vistas.