Pampas - Climate

Climate

The climate of the Pampas is generally temperate, gradually giving way to a more subtropical climate in the north, and to an arid climate on the west and the south. Summer temperatures are more uniform than winter temperatures, ranging from 20 °C (68 °F) to 32 °C (90 °F) in the north, 17 °C (63 °F) to 30 °C (86 °F) in most of the areas, and from 15 °C (59 °F) to 27 °C (81 °F) along the Atlantic coast. Extremely hot days might reach over 40 °C (104 °F).

Fall arrives gradually in March, and peaks in April and May. In April, highs will range from 20 to 25 °C (68 to 77 °F) and lows from 9 to 13 °C (48 to 55 °F). The first frosts arrive in mid-April in the south, and in late May or early June in the north.

Winters are generally mild, although cold waves do occur. Normal temperatures range from 12 to 19 °C (54 to 66 °F) during the day, and from 1 to 6 °C (34 to 43 °F) at night. With strong northerly winds, days of over 25 °C (77 °F) can be recorded almost everywhere, whereas during cold waves, high temperatures can be only 6°C (43F). Frost occurs everywhere in the Pampas, although it is much more frequent in the southwest, and less so around the Parana and Uruguay rivers. Temperatures under −5 °C (23 °F) can occur everywhere, whereas values of −10 °C (14 °F) or lower are confined to the south and west. Snow never falls in the northernmost third, and is rare and light elsewhere, except for exceptional events where depths have reached 30 cm (12 inches).

Springs are very variable, it is warmer than fall in most areas (especially in the west) but significantly colder along the Atlantic. Violent storms are more common, as well as wide temperature variations: days of 35 °C (95 °F) can give way to nights of under 5 °C (41 °F) or even frost, all within the same week.

Precipitation ranges from 1,200 millimetres (47 in) in the northeast, to about 500 millimetres (20 in) in the southern and western edges. In the west, it is highly seasonal, with some places recording averages of 120 millimetres (4.7 in) monthly in the summer, and only 20 millimetres (0.8 in) monthly in the winter. The eastern areas have small peaks in the fall and in the spring, with relatively rainy summers and winters that are only slightly drier. However, where summer rain falls as short, heavy storms, winter rain falls mostly as cold drizzle, so that the amount of rainy days is fairly constant. Violent thunderstorms are common in the spring and summer, bringing heavy rain, hail, winds and even tornadoes.