Summer 2015 officially ended across the northern hemisphere on Monday with hot conditions again gripping central parts of Europe. Poland had some of the highest temperatures, with Warsaw recording 35C (95F), about 12 degrees above the seasonal average. The latest heatwave added to what has been a very hot summer in Europe, with high temperatures combining with drought and causing widespread crop failure in Poland, Czech Republic and Romania. As the northern summer ends the hurricane season across the Atlantic reaches its peak. In the last week two tropical cyclones formed. Erika tore its way through the Caribbean depositing about 33cm (13in) of rain in just 12 hours across the island of Dominica, leaving 20 people dead in its wake. Later it dumped 16cm of rain across Charleston, South Carolina, creating the fifth wettest day on record. Hurricane Fred then developed much further east across the Atlantic Ocean. It should decay in open water over the coming days. Despite Erika and Fred, the hurricane season overall is quieter than an average year thanks to the ever strengthening El Niño dampening storm activity across the tropical Atlantic. The El Niño phenomenon, the strongest since 1997-98, according to the Australian Bureaux of Meteorology reporting on Tuesday, is often blamed for unusual, devastating, weather across many areas of the globe. But, as well as reducing the number of life-threatening hurricanes El Niño could also end a four-year drought that’s been gripping California, bringing possibly rain-bearing clouds over the unusually warm seas of the Pacific.