Santiago del Estero lies in a transition zone between more temperate climates, typical of the Pampa, and the hotter climates of the Chaco region: while daytime highs are decidedly very hot, nights tend to cool down more than most locations in the Chaco. The city is notorious for its very hot summer weather: the average high is 34°C (93F) and 40°C (104F) are attained on a regular basis; the highest temperature on record is 46.4°C (115.5F). Night time temperatures are 20°C (68F) in midsummer. There is a very short, wetter season in December and January, with up to 140 mm (5.5 in) monthly; however, this rain falls during a handful of very strong thunderstorms, and so the amount that falls on a given year is extremely variable. Fall is still warm, with average highs of 26°C (79F) in April, and lows of 15°C (59F). Temperatures can still soar to 40°C (104F) in this season. Rainfall is scarce, and becomes practically 0 for 5 months: in August, only 2.4 mm (0.09 inches) are expected. Winters bring very pleasant days (20°C, or 68F) with markedly colder nights (under 6°C, or 43F). Nonetheless, these averages are obtained through an alternance of heat waves and cold waves: short periods of 28°C to 35°C (82F to 95F) are followed by frosty days with highs around 12°C (54F), and sometimes the thermometer fails to reach 8°C (46F). The thermometer does descend below -5°C (23F), and the record low is -13°C (8.6F). Late in the winter, heat waves become much more common, and in September, 40°C (104F) are already possible. The pattern of intense heat waves followed by cool, windy weather is typical of spring, which is also very dry in Santiago. The high temperatures, extreme dryness and high winds create a very dusty environment. In October, the average high is already 31°C (88F), and rainfall only arrives in late November. December is as hot as January, and the abundant rains make the landscape green for a few months. Total precipitation is low, 593 mm (23.3 in), and
