<P> Mars' dust storms can kick up fine particles in the atmosphere around which clouds can form . These clouds can form very high up, up to 100 km (62 mi) above the planet . The clouds are very faint and can only be seen reflecting sunlight against the darkness of the night sky . In that respect, they look similar to the mesospheric clouds, also known as noctilucent clouds on Earth, which occur about 80 km (50 mi) above our planet . </P> <P> Measurements of Martian temperature predate the Space Age . However, early instrumentation and techniques of radio astronomy produced crude, differing results . Early flyby probes (Mariner 4) and later orbiters used radio occultation to perform aeronomy . With chemical composition already deduced from spectroscopy, temperature and pressure could then be derived . Nevertheless, flyby occultations can only measure properties along two transects, at their trajectories' entries and exits from Mars' disk as seen from Earth . This results in weather "snapshots" at a particular area, at a particular time . Orbiters then increase the number of radio transects . Later missions, starting with the dual Mariner 6 and 7 flybys, plus the Soviet Mars 2 and 3, carried infrared detectors to measure radiant energy . Mariner 9 was the first to place an infrared radiometer and spectrometer in Mars orbit in 1971, along with its other instruments and radio transmitter . Viking 1 and 2 followed, with not merely Infrared Thermal Mappers (IRTM). The missions could also corroborate these remote sensing datasets with not only their in situ lander metrology booms, but with higher - altitude temperature and pressure sensors for their descent . </P> <P> Differing in situ values have been reported for the average temperature on Mars, with a common value being − 55 ° C (218 K; − 67 ° F). Surface temperatures may reach a high of about 20 ° C (293 K; 68 ° F) at noon, at the equator, and a low of about − 153 ° C (120 K; − 243 ° F) at the poles . Actual temperature measurements at the Viking landers' site range from − 17.2 ° C (256.0 K; 1.0 ° F) to − 107 ° C (166 K; − 161 ° F). The warmest soil temperature estimated by the Viking Orbiter was 27 ° C (300 K; 81 ° F). The Spirit rover recorded a maximum daytime air temperature in the shade of 35 ° C (308 K; 95 ° F), and regularly recorded temperatures well above 0 ° C (273 K; 32 ° F), except in winter . </P> <P> It has been reported that "On the basis of the nightime air temperature data, every northern spring and early northern summer yet observed were identical to within the level of experimental error (to within ± 1 ° C)" but that the "daytime data, however, suggest a somewhat different story, with temperatures varying from year - to - year by up to 6 ° C in this season . This day - night discrepancy is unexpected and not understood". In southern spring and summer, variance is dominated by dust storms which increase the value of the night low temperature and decrease the daytime peak temperature . This results in a small (20 ° C) decrease in average surface temperature, and a moderate (30 ° C) increase in upper atmosphere temperature . </P>

Approximately what is the minimum surface temperatures (°c) of mars