The work describes diurnal meteorological and biometeorological conditions in June 2019 in the urban areas of Central Europe. UTCI, STI, Oh_H, WL, and OV indices were calculated based on 24-h data from Bydgoszcz (Poland) for hot days. The degree of risk connected with heat stress of different intensities, risk of hyperthermia, body water loss, and decreased oxygen volume was determined. The studies showed that June 2019 was an example of an extreme situation with a heatwave that generated high stress for the inhabitants of urban areas. The conditions were burdensome mostly due to "very strong" and "strong" heat stress and periodic risk of dehydration, situations that could quickly lead to overheating of the body and a decreased oxygen volume leading to stress.