page_title: Climate of Argentina
section_title: Northwest
hierarchical_section_title: Climate of Argentina / Regional climate / Northwest
caption_attribution_description: Deutsch: Altiplano nahe San Antonio dlC
context_page_description: The climate of Argentina is a vastly complex subject, as the vast size of the country and wide variation in altitude make for a wide range of climate types. Summers are the warmest and wettest season in most of the country except in most of Patagonia where it is the driest season. Winters are normally mild in the north, cool in the center and cold in the southern parts experiencing frequent frost and snow. Because southern parts of the country are moderated by the surrounding oceans, the cold is less intense and prolonged than areas at similar latitudes in the northern hemisphere. Spring and autumn are transition seasons that generally feature mild weather.
  Many regions have different, often contrasting, microclimates. In general, northern parts of the country are characterized by hot, humid, rainy summers and mild winters with periodic droughts. Mesopotamia, in the northeast is characterized by high temperatures and abundant precipitation throughout the year with droughts being uncommon. West of this lies the Chaco region, which is the warmest region in Argentina.
context_section_description: Northwest Argentina consists of the provinces of Catamarca, Jujuy, La Rioja, and western parts of Salta Province, and Tucumán Province. Although Santiago del Estero Province is part of northwest Argentina, much of the province lies in the Chaco region. Northwest Argentina is predominantly dry, hot, and subtropical. Owing to its rugged and varied topography, the region is climatically diverse, depending on the altitude, temperature and distribution of precipitation. Consequently, the vegetation will also differ. Under the Köppen climate classification, the region has five different climate types: semi–arid (BS), arid (BW), temperate without a dry season and temperate with a dry season (Cf and CW respectively), and, at the highest altitudes, an alpine.
  Precipitation is highly seasonal and mostly concentrated in the summer months. It is distributed irregularly due to the country's topography although it generally decreases from east to west. The eastern slopes of the mountains receives between 1,000 and 1,500 mm (39 and 59 in) of precipitation a year, though some places receive up to 2,500 mm (98 in) annually owing to orographic precipitation. The high rainfall on these first slopes creates a thick jungle that extends in a narrow strip along these ranges. The temperate valleys, the location of major cities such as Salta and Jujuy, have an average precipitation ranging between 500 and 1,000 mm (20 and 39 in), with rainfall mainly concentrated in the summer months, often falling in short but heavy bursts. Valleys in the southern parts of the region are drier than those in the north due to the greater height of the Andes and the Sierras Pampeanas on the eastern slopes than the northern mountains, presenting a significant orographic barrier that blocks moist winds from the Atlantic and Pacific oceans. These valleys receive less than 200 mm (8 in) of precipitation per year and are characterized by sparse vegetation adapted to the arid climate. The area further west in the Puna region, with an average altitude of 3,900 m (12,800 ft), is mostly a desert due to the blocking of the easterly winds by the Andes and the northwest extension of the Sierras Pampeanas. Precipitation in the Puna region averages less than 200 mm (8 in) a year while high isolation, strong winds, and low humidity exacerbate the dry conditions.
  Temperatures in northwest Argentina vary by altitude. The temperate valleys have a temperate climate, with mild summers and dry and cool winters with regular frosts.In the Quebrada de Humahuaca valley, mean annual temperatures range from 12.0 to 14.1 °C (53.6 to 57.4 °F), depending on altitude. In the Calchaquí Valleys in Salta Province, the climate is temperate and arid with large thermal amplitudes, long summers, and a long frost-free period. In the valleys in the south in La Rioja Province, Catamarca Province and the southwest parts of Santiago del Estero Province, which is part of the arid Chaco ecoregion, temperatures during the summer are very high, averaging 26 °C (79 °F) in January while winters are mild, averaging 12 °C (54 °F). Cold fronts from the south bringing cold Antarctic air can cause severe frosts in the valleys of La Rioja Province and Catamarca Province. In contrast, the Zonda wind, which occurs more often during the winter months, can raise temperatures up to 35 °C (95 °F) with strong gusts, sometimes causing crop damage. Temperatures in the Puna region are much colder, with a mean annual temperature of less than 10 °C (50 °F) owing to the high altitude. The Puna region is characterized by being cold with a large diurnal range but sunny throughout the year.
caption: The Altiplano is characterized by a cold, arid but sunny climate with large diurnal ranges.
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 350D DIGITAL", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2008:03:11 17:27:06", "Image ExifOffset": "175", "EXIF ExposureTime": "1/250", "EXIF FNumber": "8", "EXIF ExposureProgram": "Landscape Mode", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2008:03:11 17:27:06", "EXIF DateTimeDigitized": "2008:03:11 17:27:06", "EXIF ShutterSpeedValue": "3027/380", "EXIF ApertureValue": "6", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "135", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1280", "EXIF ExifImageLength": "853", "EXIF FocalPlaneXResolution": "118627/30", "EXIF FocalPlaneYResolution": "150433/38", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard"}