Map from Google - Pantanal

The climate of the Pantanal is tropical, with hot and rainy summers, and dry and sunny winters, characterized by warm days and quite cool nights. Being in the southern hemisphere, the seasons are reversed compared with Europe or North America.
Here are the average temperatures of the city of Corumbà, located in the south-central part of the region.
Average temperatures - Corumbá
CorumbáJanFebMarAprMayJunJulAugSepOctNovDec
CorumbáJFMAMJJASOND
Min (°C)232323212017181820222323
Max (°C)333232312827272931333333
Min (°F)737373706863646468727373
Max (°F)919090888281818488919191

The rains are concentrated in the warm period, from October to April, with a peak between November and February, when they approach or exceed 200 millimetres (8 inches) per month. The rainfall amount varies between 1,000 and 1,300 millimetres (40 and 51 inches) per year, and thus it is not so abundant, yet the Pantanal is the largest wetland in the world, since there are major rivers such as the Paraguay and its tributaries, which overflow in the rainy season.
Here is the average precipitation.
Average precipitation - Corumbá
CorumbáJanFebMarAprMayJunJulAugSepOctNovDecYear
CorumbáJFMAMJJASONDY
Prec. (mm)180140140805540302545901151551100
Prec. (in)7.15.55.53.12.21.61.211.83.54.56.143.3
Days1815141064557121517128

Most of the Pantanal is located in Brazil, in the states of Mato Grosso and Mato Grosso do Sul, but there is also a part in eastern Bolivia, along the border with Brazil, and a small portion in northern Paraguay. Since it hosts an extraordinary variety of plant and animal species (such as jaguars, capybaras, tapirs and hyacinth macaws), the Pantanal was declared a World Heritage Site by UNESCO in 2000.

Hyacinth macaw

Winter, from mid-May to mid-August, is dry, with rare showers. During the day it's hot, especially in the north, where the temperature fluctuates normally around 31/32 °C (88/90 °F) (see Caceres), while it remains lower, around 27/28 °C (81/82 °F), in the southern part (see Corumbà). Sometimes, however, it can be very hot even in winter, with peaks of 35 °C (95 °F) in the south and 37 °C (99 °F) in the north.
Nights are usually cool, with minimum temperatures around 15 °C (59 °F) in the southernmost part, and possible mists or fogs at night, but sometimes it can get cold, when the winds blow from Argentina, so that minimum temperatures can reach as low as 0 °C (32 °F) in the southern part, and 5/7 °C (41/45 °F) in the north.

In spring, from mid-August to mid-November, the temperatures begin to rise, and it gradually becomes the hottest season of the year, especially in the north: in Caceres the maximum temperatures hover around 34 °C (93 °F) between August and November, with peaks of 40 °C (104 °F); to the south the temperatures are lower by a couple of degrees Celsius, but the peaks are equally around 40 °C (104 °F). In September, the first rains begin to appear, though rarely, generated by the growing heat, but only in October they reach a certain size, so that in this month the rains amount to about 100 mm (4 in) per month in the south-central, and 130 mm (5.1 in) in the north.

Summer, from mid-November to late March, is hot, humid and rainy. Rainfall occurs mostly in the form of intense downpour or thunderstorm. In this period the floods make it difficult to get around. We have seen how the hottest time of the year is the spring, at the end of the dry season, but in fact sometimes the temperature can approach 40 °C (104 °F) even in summer, during hot and sunny periods, which can occur even in this season.

In autumn, from April to mid-May, there's a gradual decrease in both the temperatures and the rains. Even the rivers get back in their banks.

The amount of sunshine in Pantanal is never great, nor poor, because the sun can shine in all seasons; in any case, it is better in the winter season.

Pantanal

When to go

The best time to visit the Pantanal is the austral winter, from mid-May to mid-August, being the coolest and driest of the year. You must be equipped for the cold at night, and dress in layers, because during the day it can be hot. Even autumn, from April to mid-May, is a good period: it is hotter, especially in April, there may be some more showers, but it is also less likely that it gets cold at night.