This is a Pacific wide phenomenon where essentially, an irregular Pacific Ocean current affects the weather across 25% of the Earth's surface. This current, called El Nino, forms part of a larger system called the Southern Oscillation.

In El Nino years the direction is reversed of rain bearing winds which head to the South American coast instead of towards south east Asia. Abnormal weather patterns are associated with El Nino, from storms, to floods and mudslides in the Americas, and drought in SE Asia. The unusually high temperatures combined with the dry conditions, produce bushfires and their side effect smog. El Nino is part of the natural variability that is built into the world's weather. Try looking at some of these links which talk about the different theories of why El Nino happens:

• NOAA (National Oceanic and Atmospheric Administration)
• Educational Links from NOAA
• El Niño - The Basics
• What is an El Niño?
• Frequently asked questions about El Niño and La Niña
• USGS News and Information on El Niño