Argentina is a big country, and there are wide seasonal and geographic variations in weather. On most of our trips to Argentina, it’s important to be prepared for a wide range of weather conditions.
Many people traveling to Argentina are spending some part of the trip in Patagonia. Patagonia has weather like Alaska, with a mix of sun, rain and wind on almost any given day. From late September to mid April (the main travel season) the temperatures vary from the 40s to mid 60s during the day, sometimes a bit higher for stretches when the sun stays out. At night it will typically be in the 30s but can drop down into the 20s. The wind in Patagonia is highly variable and can be very strong; you should be sure to pack some type of shell over layer or other wind protecting jacket.
Buenos Aires has a climate like that of a southern American city, such as Atlanta. In their summer months (Dec to March), it can be very hot, into the 80s and 90s during the day. In the winter months (June to Sept), it can be quite cold, down into the 40s. In the shoulder seasons of fall and spring the temperatures are mild and pleasant.
The Lake District around Bariloche has a climate like the Pacific Northwest of the United States, but with the seasons reversed. The best time to visit is from October to April, when there is a pleasant mountain climate. Rain can still fall during this part of the year, but it will generally be short-lived and much of the day will be clear. The wet season is from May to October, and it rains fairly predictably and consistently during these times, though there can be periods of better weather.
Iguazu has a sub-tropical climate, and is surrounded by rainforest, with temperatures varying from the 60s and 70s (June and July) up into the 80s and 90s (December and January). It is an area of high precipitation. The falls are generally active and impressive all year, but are at their heaviest in the summer months of December to March and their least heavy in the winter months of June to August. The chances of the falls being dry are remote no matter when you visit. It only happens every few years during major droughts.
Mendoza is a pleasant place to visit all year round. The climate is extremely dry throughout the year, and there is abundant sun. In the summer months of December to March the temperature is usually in the 80s during the day and 60s at night. In the spring and fall, it wil drop about 10 degrees, and in the winter of June to September it will drop about 10 degrees more.