Argentina in December: weather, crowds and the best regions

Argentina in December is early summer, and the country splits in two. The south is at its best: Patagonia is dry, mild and light until around ten at night. The north is hot and entering its rainy season, with Iguazú and Salta among the wettest places in the country this month. Buenos Aires and Mendoza sit in between, warm to hot and mostly sunny. Plan the trip around that split, and around three dates on the Argentine calendar that fill flights and hotels, and December is one of the easiest months of the year to travel here.

We plan trips across the whole country every December, and this guide puts the official climate normals for seven destinations side by side, with the daylight we calculated for each and the local holidays that change prices and crowds. If you already know the route you want, a 10 day Argentina itinerary shows how the regions connect by air; if you would rather have the trip designed around your dates, that is what we do at Argentina Pura.

Argentina weather in December, region by region

These are the 1991 to 2020 normals published by the Servicio Meteorológico Nacional (SMN), Argentina’s weather service, for the airport or observatory of each destination. We cross-checked them against the WMO 1991 to 2020 series compiled by Climats et Voyages, which agrees within a degree or two; the figures for Bariloche, and the rainy days for Mendoza, Bariloche and Ushuaia, come from that series.

Destination	Average high	Average low	December rain	Rainy days
Salta	28 °C (83 °F)	16 °C (61 °F)	138 mm	13
Iguazú	31 °C (88 °F)	20 °C (68 °F)	219 mm	10
Mendoza	32 °C (90 °F)	18 °C (65 °F)	25 mm	3
Buenos Aires	29 °C (84 °F)	19 °C (65 °F)	123 mm	9
Bariloche	21 °C (70 °F)	6 °C (43 °F)	25 mm	4
El Calafate	18 °C (64 °F)	6 °C (43 °F)	10 mm	3
Ushuaia	13 °C (55 °F)	5 °C (40 °F)	43 mm	9

Three things stand out once the numbers are next to each other:

• The rain is in the north. Iguazú gets more than twenty times the December rain of El Calafate, and Salta is entering its wet season: in the same SMN normals it gets 138 mm in December and 197 mm in January, out of 738 mm in a whole year.
• The heat is in Mendoza and Iguazú, not in Patagonia. A 32 °C afternoon in the vineyards is a reason to start tastings early, not to skip them.
• Patagonia is dry and cool. El Calafate averages under three rainy days in December. What it does have is wind, which no table of averages captures well.

December daylight: three and a half hours of difference in one country

The figure that changes how you plan a December day is not the temperature, it is the light. We calculated the daylight on 15 December for each destination with the NOAA solar position equations (sunrise and sunset at 0.833 degrees below the horizon):

Destination	Daylight on 15 December
Salta	13.7 hours
Iguazú	13.7 hours
Mendoza	14.3 hours
Buenos Aires	14.5 hours
Bariloche	15.1 hours
El Calafate	16.4 hours
Ushuaia	17.3 hours

That is three and a half hours more light at the bottom of the country than at the top, on the same day. By the same calculation the sun sets at 21:55 in El Calafate and at 19:25 in Iguazú. In practice it means a boat to the Perito Moreno Glacier in the morning and a walk to a viewpoint after dinner, in daylight, which is something no other month allows. In the north the day ends earlier and hotter, which is why our December days in Salta and Iguazú start at breakfast.

The calculation gives the ceiling, not the forecast: cloud cover and mountains shorten the useful day, especially in the Andes.

Where Argentina is at its best in December

Not every region is at its peak at the same time. In December, the order runs from south to north.

Patagonia: the month the south was made for

December is the heart of the Patagonian season. El Calafate’s dry, long days are the best of the year for the Perito Moreno Glacier, and El Chaltén’s trails toward Fitz Roy are open and passable. Ushuaia is cool, around 13 °C in the afternoon, and has the longest days in the country. Our guide to Patagonia in December goes into each side of the Andes in detail, and our Patagonia tours page has the routes we build for this month.

The one thing to plan around is the wind. It is a feature of the Patagonian summer, and it is the reason we keep a margin day on any December itinerary that includes a boat or a long hike.

Bariloche and the Lakes: warm days, cool nights

With an average high of 21 °C and only four rainy days, Bariloche is in the sweet spot of its summer. It is the season for the lake crossings, and the nights, around 6 °C, still need a jacket. It is a gentle place to break up the long flights between the north and the far south.

Buenos Aires: hot afternoons and summer storms

Buenos Aires in December means 29 °C afternoons, humid air, and around nine days with rain, often as thunderstorms rather than grey days. We plan the city’s walking in the morning and leave the afternoons for museums, cafés and a long lunch. Our Buenos Aires tours are built to that rhythm.

Mendoza: dry heat in the vineyards

Mendoza is the hottest stop on most December routes and also one of the driest, with three rainy days in the month. The vines are in leaf and the days are long. Tastings and lunches at the wineries work best before the heat of the afternoon, and our Mendoza tours are scheduled that way.

Iguazú: heat, humidity and heavy rain

December is one of the wettest months at the falls, with 219 mm on average over about ten days, and humidity close to 80 %. We would not plan a single day at Iguazú in December: two nights give you a second chance at the trails if the first morning is lost. Our Iguazú Falls tours include both sides.

Salta and Jujuy: the start of the rainy season

This is the region where December asks the most of you. Salta averages 13 rainy days and 138 mm, and the summer storms can disrupt the mountain roads that make the north worth visiting. It is still possible, and the valleys turn green, but it is the region we would visit in another month if the trip allows. If it does not, keep the long drives to the mornings and leave slack in the schedule. Our Salta tours page lists what runs in summer.

Crowds and holidays: the three dates that move the country

Foreign visitors are only half of December’s demand. The other half is Argentina itself, and three dates on the local calendar decide when flights and hotels fill:

1. Saturday 5 to Tuesday 8 December 2026. Tuesday 8 is a national holiday (the Immaculate Conception), and the government has declared Monday 7 a non-working day for tourism, which makes it a four day weekend. Domestic demand peaks over those four days, so book any flight that touches them early.
2. 17 to 23 December 2026. The school year ends: on 18 December in the City of Buenos Aires, Córdoba and Santa Fe, and on 22 December in Buenos Aires Province and Mendoza, according to the 2026 school calendar agreed by the Federal Council of Education. Summer holidays start the next day, and family travel starts with them.
3. Christmas and New Year. Friday 25 December and 1 January are national holidays. Christmas Eve and New Year’s Eve are family nights in Argentina, so book those two dinners well ahead.

The practical reading: the first half of December, outside the long weekend, is the quietest stretch of the Argentine summer. From the 18th, domestic demand climbs into January and February, the core of the Argentine summer holidays. If your dates are flexible, travel before the schools close; if they are not, book the domestic flights first.

Things to do in Argentina in December

The month rewards the outdoor half of the country. These are the experiences we build December trips around, in the order the weather favours them:

• Walking on the Perito Moreno Glacier, or watching it from the walkways and the boat, on the longest days of the year.
• Trekking around El Chaltén toward Fitz Roy, with the trails open and the light lasting into the evening.
• Navigating the Beagle Channel from Ushuaia, the gateway to the Antarctic season that is in full swing this month.
• Crossing the lakes around Bariloche, warm enough to sit on deck.
• Lunch among the vineyards in Mendoza, early in the day and with the Andes behind the table.
• Christmas in Buenos Aires, in summer heat.

Our guide to things to do in Argentina covers each region in more depth and how many days each one needs.

A December route that follows the weather

Put the climate table and the calendar together and the shape of a December trip almost draws itself: a short stay in the north, then Buenos Aires, then south for as long as you can.

1. Iguazú, two nights, early in the month.
2. Buenos Aires, three nights, with the mornings for walking.
3. El Calafate, three nights, for the glacier.
4. El Chaltén or Ushuaia, two or three nights, depending on whether you want trails or the Beagle Channel.

That is ten to eleven nights, close to the route in our 10 day Argentina itinerary, turned to face the December weather.

On cost, December is high season in Patagonia; our guide to whether Argentina is cheap to visit sets out what a day costs in each region and what sits outside a tour price.

Is December a good time to visit Argentina?

Yes, if you build the trip from the south. December gives you Patagonia at its best, the longest days of the year, and a first half of the month that is quieter than the summer that follows. It asks for flexibility in the north, where the rains begin, and early booking around the 5 to 8 December weekend and the Christmas week.

Tell us your dates and what you want from the trip, and we will design it around the December weather and the Argentine calendar, with the domestic flights booked in the right order. Start with Argentina Pura and our team will take it from there.