So as I've said before, I have though about some of the interesting tidbits of information dropped in Star Trek about some of the more significant planets.

So from the home of the constant allies of humanity the Vulcans, we move to the homeworld of one of it's more sinister enemies the Cardassians:

Cardassia Prime:
There are two important sets of information about Cardassia Prime in Star trek cannon to help us gather some useful information about the world. The first actually appears to be a set of inconsistencies in TNG and DS9. The other set is from collective subtle clues from the Cardassians themselves.

In one of the TNG episodes where we encounter the Cardassians for the first time, Picard states that the current Cardassian government came to power less around 100 years ago, but Gul Dukat seems to say that it's over 500 years old in DS9. Also in most cases the Dominion is indicated to be 2,000 years old by the time of DS9, even by Dominion members, but in at least one case a Vorta indicates the Dominion is around 10,000 years old. This can be rectified easily if the Cardassian year (Gul Dukat's perspective) is about 1/5 the length of an Earth year (Picard's perspective).

The other sets of clues begin with the standard pale or even outright white skin tones of the Cardassians themselves. This is then followed by the fact than on board Cardassian ships and space stations, and even in Cardassian residences, there is very little light similar to dawn or dusk. There is also the fact that Cardassians have very low tolerance for cold, and that environments comfortable to Cardassians are often described as hot by humans or other species. Finally there is the fact that Cardassia Prime at least is described as poor in resources, but even though they had interstellar contact (and presumably warp drive) some 300 years prior to DS9, only reached Bajor, some 5 to 6 light years away about 50 years ago.

Finally the final piece of information comes from an okudagram of the Cardassian system that clearly places Cardassia Prime as the second planet of the system, and the surface of Cardassia IV is shown to be habitable, likely placing it inside the Cardassian habitable zone.

A year of only (approximately) 73 Earth days long requires Cardassia Prime to orbit it's sun much closer than Earth dose it's own sun. Also the lack of skin pigmentation in general and preference for lower lighting conditions suggest a significantly less luminous sun than Earth's. The lack of adaptation to cold climates and reptilian-like features that might be the product of a warmer and less severe climate, that can be expected from a more significant concentration of greenhouse gasses in the atmosphere of Cardasssia Prime. Finally there is the fact that the Cardassians took at least 50 years, if not centuries to take notice of Bajor, even though they were practically next door by interstellar standards. A planet, possibly tidally locked, in orbit of a low metalissity M type main sequence red dwarf would be expected to have conditions consistent with Cardassia Prime for the most part. The sun would produce much less light in the visible portion of the spectrum, and more in the infra-red, resulting in lower light in daylight conditions. To avoid the atmosphere freezing out, potentially similar to Remus, a concentration of a partial pressure of 0.15 bars of carbon dioxide, much more than you find on Earth and could result in a clement or even warm climate across the entire surface of Cardassia Prime, even in night conditions. Also there is every indication that Bajor orbits a much more sunlike star, that Cardassian astronomers may have discounted as being too unlike their own sun to support habitable planets for potential colonization.

So a more scientific description of Cardassia Prime might be as follows:
2nd Planet from the Cardassian sun, a dim red dwarf, and the innermost of three planets in the system's habitable zone, with an orbital period of 73 Earth days. The innermost planet is a hot, dry tidally locked world. The third and fourth planets have been terraformed by the Cardassians to suit their needs, but like Cardassia Prime are poor in heavy elements, necessary for Cardassian industry. The outer planets are frozen worlds, of the "icy super-earth" variety, increasingly composed of volatiles the further out they are located.