Airborne microphysical and optical properties of mid-latitude cirrus clouds were measured at temperatures ranging from -25°C to -62°C in the Southern hemisphere from Punta Arenas (53°S) in March and April 2000 during the INCA experiment (Interhemispheric differences in cirrus properties from anthropogenic emissions). The observations show general decreases of the ice water content (18 mg m-3 to 0.05 mg m-3), extinction coefficient (0.70 km-1 to 0.08 km-1), ice particle concentration (2.2 cm-3 to 0.5 cm-3), and the effective diameter (80 mm to 17 mm) linked to the variation of ambient temperature (-25°C to -60°C). The lowest temperature at which supercooled water droplets were detected was -33°C. The asymmetry parameter shows relatively small variations with the smallest values (0.758) observed at the lowest temperatures. The optical phenomenon related to the 22° halo indicating the occurrence of pristine ice crystals is preferentially found between -40°C and -55°C. Cirrus clouds which form with a rapid vertical transport, i.e., jet-stream cirrus, wave-cirrus, and cirrocumulus, are characterised by very high values of the ice particle concentrations (up to 100 cm-3) compared to the mean values as a whole (1.45 cm-3). The results of two case studies related to a jet-stream cirrus and orographic-wave cirrus are presented with details.