Forecasters say there is a risk of a "very strong" El Nino, which typically leads to higher global temperatures and drought in some areas, but heavy rainfall in others.
Petrol stations in the Russian-held Crimea had run dry on Thursday, witnesses said, after Ukraine stepped up drone strikes on supply lines to the peninsula.
Experts have called the filming of a close encounter between divers and a great white shark in the Mediterranean Sea an "exciting" moment - but warned little is understood about the region's shark population.
The powerful sister of North Korean leader Kim Jong Un has declared that the country will never surrender its nuclear-armed status and continue to expand its atomic arsenal.