Climatic map of the Province of La Pampa, Argentina
Being located in the Pampas, the province has a cool temperate climate. In general, the province is dominated by two different types of climates: a temperate one in the east and a semi-arid one in the west. Precipitation generally decreases from east to west and from north to south. Being characterized by large thermal amplitudes, the climate of the province has continental characteristics, particularly in the west where thermal amplitudes are much larger. The general atmospheric circulation is one of the most important factors that influence the climate on a regional scale. During summer, the South Atlantic High is displaced to the southeast, which brings hot and humid air masses from the north and northeast. The South Pacific High in summer is responsible for bringing cooler air masses from the southwest which when these two contrasting air masses meet lead to precipitation occurring. In contrast, winters are dry due the northward displacement of the South Atlantic high and the topographic barrier of the Andes north of 40oS which prevents frontal systems that bring precipitation from reaching the province. Any winds from the southwest during winter bring in cold and dry weather since most of the precipitation and humidity are released in the Andes. As such, most of the precipitation occurs during summer.
Temperature: Mean annual temperatures in the province range between 14 to 16 °C although the thermal amplitude (difference between temperatures in the warmest and coldest months) is large. In summer, mean temperatures in the warmest month (January) range from 24 °C in the north and northeastern parts to 22 °C in the west and southwestern parts of the province. Temperatures tend to be cooler in the west owing to the higher altitudes. In winter, mean temperatures in the coldest month (July) range from 8 °C in the north to 6 °C in the west and southwest. The northern parts are the warmest parts of the province; absolute maximum temperatures can reach up to 40 to 45 °C. The lowest temperatures ever recorded range from ?10 °C in the northeast to ?17 °C in the southwest.
Precipitation: One characteristic of the precipitation in the province is that most of the precipitation occurs from October to March with little precipitation during winter. Mean annual precipitation ranges from a low of 260 mm in the southwest to 820 mm in the northeast. Precipitation generally decreases from northeast to southwest. Most of the precipitation is caused by frontal systems. Precipitation is highly variable from year to year.