Tokyo has been seeing its summers grow hotter. In 2004, temperatures in Tokyo topped 86 degrees Fahrenheit for 41 days in a row, a record. The high temperatures in Tokyo during the summer of 2007 averaged around 85 degrees Fahrenheit. The increasing heat has been attributed to global warming, heat island effect and mock El Nino. The heat has placed increasing demands on Tokyo’s power system, as people try to stay cool indoors.