Seasons

Winter

In winter major winds include the cool Pampero blowing on the flat plains of Patagonia and the Pampas after a cold front; a warm wind that can blow from the north in mid and late winter creating mild conditions; and the Zonda, a hot and dry wind (see also foehn wind), affecting west-central Argentina. Argentina also gets some snow in many southern and central places.

Spring

In Northern region, spring is very short, but progressively lasting more southwards (around 3 months at Buenos Aires’ latitude). During mid-October a large variety of wild and urban flora fully blossom. Thunderstoms and hailstorms are frequent. Temperatures are mild and nights are cool.

Summer

In summer temperatures are more diverse, with an average of 9 °C (48.2 °F) in the south and 27 °C (80.6 °F) in the north. Temperatures can reach up to 45 °C (113 °F) in rn parts, but by a short period. Cold fronts are frequent, lowering temperatures as much as 15 °C (27.0 °F).

Autumn

Is generally mild, windy and progressively lasting more southwards (around 3 months at Buenos Aires’ latitude). Some forests and vineyards can bring along the autumn foliage, with its red and orange leafs, specially in mid-April. During these season, the arrival of night becomes noticeably earlier but later on it becomes a distraction.

Climate

Northwest & Gran Chaco Regions

The Northwest region stands out for its warm weather; with mountains of various colours, the Puna highlands, valleys and ravines, and the characteristic towns and cities of great historical value.

Cities like Salta and Jujuy, at about 1,200 m of altitude, have pleasant, monsoon-like weather, with warm, rainy summers with pleasant nights (26°C to 29°C during the day, 14°C to 18°C at night), and extremely dry winters with mild days (19°C to 21°C) and cool nights (2°C to 5°C).

Rainfall in the summer can reach 200 mm per month, but in the winter, it is less than 10 mm per month. The first ranges of the Andes receive very high precipitation, over 2,000 mm, and are immersed in a thick fog for most of the year, producing a thick jungle.

Further west, in the Puna region next to Bolivia, altitudes range from 3,000 to 4,000 m and temperatures are much colder: nighttime lows average -8°C in July and 7°C in January, daytime highs range from 21°C in November to 15°C in June, and precipitation is low (300 mm), falling exclusively in the summer.

At low altitudes further east and south, in the Chaco, the weather is extreme: a short, mild winter from May to August, with temperatures from 20°C to 24°C and lows between 8°C and 12°C (and occasional frost) gives way to an extremely hot and dry spring and early summer, with high temperatures escalating to 30°C to 40°C and heat waves reaching 45°C, provoking tremendous droughts.

Then, starting in December, rainfall arrives in the form of severe thunderstorms, but temperatures still remain hot, climbing to 35°C to 37°C on average, with nights in the 20°C to 25°C degree range. Fall is pleasant and warm, with 25°C to 28°C, and cooler nights.

Mesopatamia

The Mesopotamia has a sub-tropical weather in the northern part and a milder climate in the southern one. It has a very diverse flora and fauna, and its territory contains hillocks, lagoons and marshes, and is crossed by large rivers.

In the far north, summers are very long and humid, but not as extreme as in the Chaco region, staying most often in the 30°C to 35°C range (18°C to 24°C at night) Falls are also warm and humid, often reaching 30°C as well, and winters are mostly mild, with highs between 20°C and 24°C, and lows around 10°C.

However, temperatures still reach 30°C on occasion, but also fall to 0°C every once in a while, and it is not uncommon to see rainy days with high temperatures hovering around 10°C and strong winds from the south. Precipitation reaches up to 2,500 mm, producing a thick jungle.

As we move south towards Entre-Rios, summers become shorter, and we perceive four distinct seasons, with pleasant falls between 20°C and 25°C, cool winters with highs in the 15°C to 18°C range, common night frosts and mild, windy springs.

Precipitation is high throughout the year, especially in early and late summer, reaching between 1,200 and 1,800 mm.

Cuyo & Central Regions

The region of Cuyo has mountainous characteristics (the Aconcagua Mountain rises in the area), and is extremely arid: many places receive less than 200 mm of rainfall annually, which fall almost exclusively between November and February.

Temperatures are, on average, similar to those in the Pampas, but they tend to be more extreme: they are known for reaching extremes of up to 45°C during heat waves, although humidity is lower than in other regions, but in some areas they can also fall below -10°C and in parts of southern Mendoza province (Malargüe), they can reach -20°C as well, with frequent (albeit thin) snow cover.

In the winter, strong Zonda winds can blow down from the Andes, melting the snow and pushing the temperatures up to 25°C even at relatively high altitudes. In the Andes, precipitation increases to about 600 mm in the south and 400 mm in the north, which fall mostly in the winter as snow: places above 2000 m in the south and above 2800 m in the north have ample snow cover for winter sports, and the passes to Chile, which reach over 4000 m, are often closed.

The Central sierras of Córdoba and San Luis possess a very benign mild and dry weather, with temperatures very similar to those of the Pampas, but cooler summer nights due to the altitude, and extremely dry winters: although nights are cold, daytime temperatures are pleasant.

Snow happens yearly but in small quantities due to the dryness, and thunderstorms in the summer can be very violent. Some spots in Córdoba receive over 1,000 mm of rain from these, and in the highest areas of the sierras, temperatures can reach -20°C on occasion.

The Pampas

The Pampas region, possesses the most productive lands in the country for agricultural and livestock activities. The plain is only interrupted by the Tandil and Ventana sierras. It has long and crowded beaches facing the Atlantic Ocean towards the east. Rainfall ranges from 1200 mm in the northeast, to a general 700 – 850 mm in most regions, to under 600 mm in the south and west.

Summers are long and hot, with average high temperatures between 29°C and 32°C (Except along the Atlantic coast, where they range from 25°C to 28°C) and nighttime lows between 18°C at the northern edge and 14°C in the south. Afternoon thunderstorms are common, as well as heat waves that can bring temperatures in the 36°C to 40°C range for a few days.

These are usually followed a day or two of strong Pampero winds from the south, which bring cool, dry air with high temperatures in the low 20s and nights often below 12°C to 15°C. Precipitation in the summer is high, with most places averaging between 90 mm and 160 mm monthly during the season.

The fall arrives in March and brings periods of very rainy weather followed by dry, mild stretches and cool nights. Across the region, daytime temperatures range from 24°C to 28°C in March (nights range from 12°C to 16°C), from 20°C to 24°C in April (nights 9°C to 12°C), and from 17°C to 21°C in May (nights from 5°C to 9°C). Places in the east receive rainfall throughout the fall, whereas in the west it quickly becomes very dry, and many places receive less than 15 mm in May.

Frost arrives in early April in the southernmost areas, but only in late May in the north. June, July and August are the core of the winter in the Pampas, and there are often drastic changes in temperature. When winds blow from the north, it is not uncommon to see temperatures between 22°C and 25°C (although nights remain cold) and some spots in the western part may even hit 30°C; however, after cold fronts from the south, highs might not reach 5°C in the west and 8°C in the east, and night time temperatures can fall below -5°C.

Generally speaking, highs range from 12°C to 19°C and lows from 1°C to 5°C, frost is common and precipitation is very scarce in the west. Snowfall is very rare in most parts, although there have been snowstorms in the past: in 2007, most of the northern pampas were covered with snow up to 20 cm in some areas, and low temperatures plummeted to -12°C in parts of Córdoba and San Luis provinces. A common feature is a strong, southeasterly wind called Sudestada, which is often accompanied by drizzle, cool weather and rough seas along the coast.

Spring is known for being very windy, and for its tremendous cold fronts and heat waves: one week, places in the Pampas can be baking with 35°C, and a week later, they can be frosty with highs around 12°C. It is also the season for violent thunderstorms and hail, but also of drought. Generally speaking, temperatures increase from the 18°C-22°C range in September (5°C-9°C at night) to 25°C-29°C in November (10°C-15°C) at night. The last frosts happen in mid-September in the north, and in November in the southernmost parts.

Patagonia

The Patagonia is the most extensive region, with much colder weather accentuated in the southern part. The west is mostly constituted by a mountainous landscape scored by spectacular woods, lakes and glaciers; it has an arid plain in the centre, and long beaches with varied marine fauna to observe to the east.

The south end of this region is the southernmost point in the world except for Antarctica. Northwestern Patagonia sees a strong precipitation gradient from the wet limit with Chile and the dry steppes: within 50 km, it can fall from 4,000 mm to 400 mm.

The Lake District there, at low altitudes, has pleasant summers between 20°C and 24°C, where temperatures over 30°C are very rare, with cold nights between 4°C and 8°C, with frost not uncommon. Winds blow constantly from the west and there can be long stretches of sunny weather; however, when it rains, temperatures might stay around 10°C even in the middle of the summer, and low-altitude snow is not unprecedented.

Fall is extremely rainy, with highs from 12°C to 15°C in April and 8°C to 11°C in May. Cold fronts can bring some early snowfall, and temperatures down to -8°C. Winter is also very rainy, but there is often sleet and snow as well, and large snowstorms with up to 30 cm of snow can happen. Temperatures are usually between 3°C and 9°C during the day, and between -5°C and 3°C at night; however, with clear skies, they often fall below -10°C and they can reach -20°C (with highs in the -5°C to -2°C) on extreme winters.

Long stretches of subzero temperatures are very rare, but intense frost is very common. Snow persists in the mountains until mid-summer at 2,000 m, and never melts above 2,500 m.

The central Patagonian plateau experiences marked contrasts: in the summer, temperatures climb to 28°C in the north and 22°C in the south, with extremes beyond 30°C; however, nights are cold with lows in the 5°C to 9°C range. Winters range between 2°C and 9°C during the day, and between -7°C and -3°C at night; however, when cold air masses move in from Antarctica, temperatures drop to incredibly low values: it is not uncommon to have large areas below -20°C, and some spots have reached -35°C.

Snowfall is common but quantities are small, and there can be longer periods of frost. Along the coast, it is significantly warmer, with most winter days reaching about 10°C and nights around 2°C, and rarely below -10°C.

The region is among the windiest on earth, with average speeds of up to 35 km per hour in the spring, and behind cold fronts, the whole region is swept with winds between 100 and 160 kilometers per hour. Extreme southerly areas in Tierra del Fuego are known for their storminess: in Ushuaia, at sea level, summer days average from 12°C to 16°C, and temperatures only reach 20°C a few times every year.

Snow can happen anytime, but only becomes frequent in April; however, temperatures are not extreme in the winter because of the Ocean: the average days are about 0°C to 5°C, nights from -5°C to 0°C, and it is very rare to see nighttime temperatures fall below -12°C on the coast (but they fall to -20°C inland, with heavy snowcover). Snow can fall in large quantities some years.

The ice fields in Santa Cruz have an extreme climate, with up to 4,000 mm falling as snow, subzero temperatures, winds over 150 kilometers per hour and constant cloud cover.