The natural phenomenon El Nino is blamed for the torrential rains.
As 2016 approaches, the ongoing El Nino shows no sign of relaxing its grip on the global climate.
Five countries – Colombia, Ecuador, Peru, Indonesia and Papua New Guinea – have declared a state of emergency, and the UN is helping another 10 countries by deploying emergency resources.
El Nino, which strictly refers to the surface warming of the eastern and central Pacific Basin, has a knock-on effect across much of the world.
This naturally occurring phenomenon, which appears every two to seven years, is particularly strong this year. It is certainly the strongest since the last major El Nino of 1997-98, and it stands every chance of being the strongest since at least 1950.
Overall, an El Nino typically adds 0.1 to 0.2C to global temperatures. That these temperatures, through most of 2015, have been running at almost 1.0C above the long-term average, suggests that the El Nino contribution to the warming planet is relatively small.
Nevertheless, at a regional level, El Nino has had a major impact on the lives of millions of people.
Ethiopia is suffering its worst drought in more than 50 years. So far, donor countries have given more than $435m to help feed people in the worst-affected areas. Yet the Ethiopian government is appealing for a total of $1.4bn to help feed more than 10 million people.
The state of emergency in Colombia, Peru and Ecuador is largely in anticipation of events, based on the last major El Nino in 1997-98. Then, heavy rain brought widespread flooding to the Pacific coastline and the fishing industry was devastated. Ecuador is thought to have lost 15 percent of its gross domestic product to El Nino.
In Indonesia and Papua New Guinea, El Nino has brought the worst drought in 18 years. Food shortages are having an effect on Papua New Guinea, where rivers have dried up, and hard frosts have decimated the garden crops of many villagers.
The Papua New Guinea National Weather Service expects El Nino to intensify and to persist until March.
In Indonesia, the drought has undoubtedly made the wildfire situation much worse. These fires have been burning since July and cover an area of more than 20,000 square kilometres. Economic losses have been calculated at more than $9m, but the damage to the environment is such that the situation has been described as the worst environmental disaster of the 21st century.
If, as predicted, El Nino eases early in 2016, many of the problems described above are likely to continue as most forecast organisations expect 2016, globally, to be the warmest on record.