When thinking about the climate on your fictional planet, it may be best to first decide on if you want a moon or if you want many. Theories have stated that if there was no moon, there would be little change in the tide as they are caused by the opposing gravities of Earth and our moon. The moon is also lengthening Earth’s day slightly over the centuries and stabilizing the axial tilt. Without the moon stabilizing the tilt, the weather patterns would be drastic as the seasons changed. Having a number of moons would make the planet rather unstable as the friction of the moons competing with each other and Earth’s gravity would cause friction heating the planet and the tides and weather would be erratic as well as the tectonic activity.
Once you’ve decided on how many moons your planet has, and how any differences could affect the fictional planet, the next step in your writing process will be to decide on the climatic zones. Take out your topography map and a few markers. If your planet is similar to Earth, get out six markers or highlighters. Climatic zones are decided by how the star’s rays hit the planet (as Earth is round, it takes longer for the rays to hit the poles than the Equator so it’s colder at the poles), How high up it is (heat may rise but higher air is thicker and doesn’t allow much space for particles to move and create heat), winds (cold winds cool the area while hot winds rise the temperature), distance from big bodies of water as they stabilize weather (think ocean effect on coasts or lake effect around the Great Lakes), and where the slope of the hill or mountain is facing towards the star or away from it. Earth’s six main climatic zones are: polar, temperate, arid, tropical, Mediterranean, and tundra. As it is your planet, you can add as many zones as you like or as few zones as you like, it would just help if it were scientifically possible as many science fiction readers these days know as more about science and real possibilities than ever before and nothing is worse than alienating readers by science they know to be impossible without an explanation somewhere.
Once you know the climate zones, we can take a look at what plants are on your planet in the next segment of how to create your fictional planet.