Heatwaves and Health: Guidance on Warning-System Development; 2015 (sólo en inglés)

Heatwaves are a pervasive natural hazard. Although there is no universally accepted definition, they are understood to be periods of unusually hot and dry or hot and humid weather that have a subtle onset and cessation, a duration of at least two–three days, usually with a discernible impact on human and natural systems.