China's weather bureau said the chance of an El Nino weather event this year is about 70 percent, which may affect China's crop output and bring conditions for drought and flooding across the country.

"An El Nino is very likely, and if formed, it is expected to reach its maximum strength during December," said Ding Yihui, a climate change adviser at the China Meteorological Administration.

El Nino is a warming of sea temperatures in the Pacific, affecting wind patterns and triggering both floods and drought worldwide. Previous El Nino events have affected crop harvests in China and caused severe droughts and water shortages.