difficult task...

[Aite]

I have been working on my planet project for quite a while, but keep bumping into one question: how to determine weather on the planet? I mean: i have specified thing such as sun size and luminosity, orpit, planet size and rotation period, day lenght, axial tilt etc. Is there any program/simulation taht would help me create my long-dreamt-of planet? I am afraid I dont have enough knowledge about how the weather works to do it myself...
I would appreciate any help, thank you.

[astromark]

Stop beating your self up about your inability to determine weather...
We have a group of professionals working for a govt., dept., and they can not tell me just five days out of it will rain or not. We live on this planet with a wealth of history and equipment to call on.
Making predictions about just how weather will actually perform is a quantum of inaccurate predictions. So to your question... How to know what a given climate will deliver is very big SCIENCE. There are so many variables it is all most impossible. I have a friend whom works as a statistician for NEWA .. He is employed to gather data from across the nation to help farming and other weather Dependant industry.They study trends of weather and erosion. Its interesting stuff. My point is with all the resources available they can not be absolute about our weather., and this is real and observable... so to 'make' a planet and to 'know' its weather is a very big ask.

[antoniseb]

... Is there any program/simulation taht would help me create my long-dreamt-of planet? I am afraid I dont have enough knowledge about how the weather works to do it myself...
...

I'm not aware of such a program. Maybe this is a business opportunity for someone. I wonder if there are enough aspiring SF writers and SF LARP creators that a climate/weather calculator tool would be commercially viable.

In the mean time, we have seven bodies in the solar system (eight if you count the Sun) that have observable weather/climate. Perhaps you can interpolate or extrapolate from what we already know.

[swampyankee]

Well, you could try downloading and compiling (after making appropriate modifications) one of the global climate modelling programs. Try browsing around for "world building."

Somebody (maybe even me!) could do that for you, but you'd have to pay.