Today, we have satellite images of Mars with a resolution of up to 24 cm per pixel. The planet has a thin atmosphere compared to Earth’s, but its surface is revealing itself to be active and complex. The use of images is an increasingly precise means of investigation for the study of transient phenomena that occur on the surface of the planet. We have developed a dating code that could be useful in the study of such phenomena. Thanks to this dating code, it is possible to immediately understand what season is in progress in the observed area starting from the terrestrial reference date of the photos taken by the orbiters. Some intermediate parameters of this calculation, such as the Martian year and the day of the year, can be equally useful for similar investigations. Satellite study of transient phenomena observable on the surface of Mars can range from geology (wind erosion and sedimentation) to meteorology (wind and phase transitions) to indigenous or non-indigenous biology.