WORCESTER, England — Britons may remember 2012 as the year the weather spun off its rails in a chaotic concoction of drought, deluge and flooding, but the unpredictability of it all turns out to have been all too predictable: Around the world, extreme has become the new commonplace.

Especially lately. China is enduring its coldest winter in nearly 30 years. Brazil is in the grip of a dreadful heat spell. Eastern Russia is so freezing — minus 50 degrees Fahrenheit, and counting — that the traffic lights recently stopped working in the city of Yakutsk.

Bush fires are raging across Australia, fueled by a record-shattering heat wave. Pakistan was inundated by unexpected flooding in September. A vicious storm bringing rain, snow and floods just struck the Middle East. And in the United States, scientists confirmed this week what people could have figured out simply by going outside: last year was the hottest since records began.

“Each year we have extreme weather, but it’s unusual to have so many extreme events around the world at once,” said Omar Baddour, chief of the data management applications division at the World Meteorological Organization, in Geneva. “The heat wave in Australia; the flooding in the U.K., and most recently the flooding and extensive snowstorm in the Middle East — it’s already a big year in terms of extreme weather calamity.”