Long-lasting periods of extreme heat - so-called heat waves - have been occurring in unusual frequency in Europe and Germany for about 30 years. The resulting health problems can be considerable, sometimes life-threatening. The summer 2018 was the second hottest since climate records started in 1881. The hottest ever summer was in 2003, which claimed over 40,000 lives in several countries in Western Europe (around 7,000 in Germany). The increased heat-related mortality primarily affects older people. The guide provides important information for a well adapted and individual protective behaviour for summer heat.