Many astronomical phenomena viewed from the planet Mars are the same as or similar to those seen from Earth; but some (e.g. the view of Earth as an evening/morning star) are quite different. For example, because the atmosphere of Mars does not contain an ozone layer, it is also possible to make UV observations from the surface of Mars.
Seasons
Mars has an axial tilt of 25.19°, quite close to the value of 23.44° for Earth, and thus Mars has seasons of spring, summer, autumn, winter as Earth does. As on Earth, the southern and northern hemispheres have summer and winter at opposing times.
However, the orbit of Mars has significantly greater eccentricity than that of Earth. Therefore, the seasons are of unequal length, much more so than on Earth:
In practical terms, this means that summers and winters have different lengths and intensities in the northern and southern hemispheres. Winters in the north are warm and short (because Mars is moving fast near its perihelion), while winters in the south are long and cold (Mars is moving slowly near aphelion). Similarly, summers in the north are long and cool, while summers in the south are short and hot. Therefore, extremes of temperature are considerably wider in the southern hemisphere than in the north.
The seasonal lag on Mars is no more than a couple of days, due to its lack of large bodies of water and similar factors that would provide a buffering effect. Thus, for temperatures on Mars, "spring" is approximately the mirror image of "summer" and "autumn" is approximately the mirror image of "winter" (if the solstices and equinoxes are defined to be the beginnings of their respective seasons), and if Mars had a circular orbit the maximum and minimum temperatures would occur a couple of days after the summer and winter solstices, rather than about one month after, as on Earth. The only difference between spring temperatures and summer temperatures is due to the relatively high eccentricity of Mars' orbit: in northern spring Mars is farther from the Sun than during northern summer, and therefore by coincidence spring is slightly cooler than summer and autumn is slightly warmer than winter. However, in the southern hemisphere the opposite is true.
The temperature variations between spring and summer are much less than the very sharp variations that occur within a single Martian sol (solar day). On a daily basis, temperatures peak at local solar noon and reach a minimum at local midnight. This is similar to the effect in Earth's deserts, only much more pronounced.
The axial tilt and eccentricity of Earth (and Mars) are by no means fixed, but rather vary due to gravitational perturbations from other planets in the Solar System on a timescale of tens of thousands or hundreds of thousands of years. Thus, for example Earth's eccentricity, currently about 1% regularly fluctuates and can increase up to 6%.
Aside from the eccentricity, the Earth's axial tilt can also vary from 21.5° to 24.5°, and the length of this "obliquity cycle" is 41,000 years. These and other similar cyclical changes are thought to be responsible for ice ages (see Milankovitch cycles). By contrast, the obliquity cycle for Mars is much more extreme: from 15° to 35° over a 124,000-year cycle. Some recent studies even suggest that over tens of millions of years, the swing may be as much as 0° to 60°. Earth's large Moon apparently plays an important role in keeping Earth's axial tilt within reasonable bounds; Mars has no such stabilizing influence, and its axial tilt can vary more chaotically.
The color of the sky
The normal hue of the sky during the daytime can vary from a pinkish-red to a yellow-brown “butterscotch” color; however, in the vicinity of the setting or rising sun it is blue. This is the exact opposite of the situation on Earth. On Mars, Rayleigh scattering is usually a very small effect. It is believed that the color of the sky is caused by the presence of 1% by volume of magnetite in the dust particles. Twilight lasts a long time after the Sun has set and before it rises, because of all the dust in Mars' atmosphere. At times, the Martian sky takes on a violet color, due to scattering of light by very small water ice particles in clouds.
Generating accurate true-color images of Mars's surface is surprisingly complicated. There is much variation in the color of the sky as reproduced in published images; many of those images, however, are using filters to maximize the scientific value and are not trying to show true color. Nevertheless, for many years, the sky on Mars was thought to be more pinkish than it now is believed to be.