2003 European heat wave2003 European heat wave Dates June 2003 to August 2003 Areas affected Mostly western EuropeThe 2003 European heat wave was the hottest summer on record in Europe since at least 1540. The heat wave led to health crises in several countries and combined with drought to create a crop shortfall in parts of Southern Europe. During the heat wave, temperatures remained at record highs even at night, preventing the usual cooling cycle. The heat wave here broke no records, although 4 tropical weather designated days in mid-July, preceding the official wave, are not counted due to a cool day in between and the nature of the Netherlands specification/definition of a heat wave. [citation needed]GrapesThe heat wave greatly accelerated the ripening of grapes; also, the heat dehydrates the grapes, making for more concentrated juice.