Fig. 1: During winter time the Brougier Park is rarely used for swimming and having picnic. Later we went diving here. The water was warmer than the air. Apple iPhone SE; Δt=1/121 s; f=4.15 mm; f/2.2; ISO 25; 8 January 2017 10:06:04Fig. 2: At dive site Riedsort nearby Weggis. The water of Lake Lucerne was about 6 °C kalt — warmer than the air. After diving it started to snow. Apple iPhone SE; Δt=1/223 s; f=4.15 mm; f/2.2; ISO 25; 10 December 2017 12:05:38