It's a bug or it's normal?

[WitheHole18]

The clouds on planets are blue,it's normal or it's a bug?

[Arian]

Depending on the temperature and the material composition of your planet's atmosphere, as well as on the color of your star's light, this could be totally normal and it was even asked for.

Actually in most cases clouds would be white, because of spectral addition effects, but whatever the atmosphere is made of may result in a different "filter". These filter effects contribute to the famous/infamous greenhouse effect by reflecting infrared light back to the surface.

[WitheHole18]

it was a red little star,but i don't know the composition of the atmosphere 

[Arian]

As of yet, nobody knows the composition of the atmosphere, because that isn't implemented so far.
For the time being, atmospheres are more or less randomly colored, so I was more generally speaking about the possibility.
It is not a bug that planets look quite different from earth. The possibilities and combinations to get a rocky planet with an atmosphere are finite but there are many.

[scruffygamer]

The clouds on planets are blue,it's normal or it's a bug?

The color depends on the planet's atmosphere color.

You know how atmospheres like change the look of light. Well that is why.

[Physics_Hacker]

Earths atmosphere is blue, yet we don't have blue clouds.

I think this applies here, because this effect, only "implemented" in the last update, happens way too often for me, at least.

[Arian]

Actually Earth has indeed blue clouds when seen from space, it's just not very saturated. As I said, normally all clouds look white for the same reason snow is looking white. Light gets reflected and refracted so between the particles that make the clouds light has all colors and goes in all possible directions, mixing up to white again.
If enough atmosphere is between you and the clouds, that atmosphere will filter out certain wavelengths. How much atmosphere is between the observer and the clouds depends on the scale height and density of the atmosphere as well as on the density of the clouds particles, also on the temperatures and pressure in certain atmosphere layers and the state or phase of matter of the cloud material.

You can watch the white cloud effect on a car's front pane when it breaks and the filter effect if you throw white noodles into a strong soup. The front pane will go from transparent into white (even though the pieces will still be transparent. The noodles will look the color of your soup and more so as they sink deeper.

However, I can't disagree that the effect seems a little exaggerated since the update. I don't mind since it adds to immersion. Once we can "compose" atmospheres that shouldn't be an issue. And yes, I do want to have a selection of possible gases to compose an atmosphere and they should correspond with the temperatures on a planet pretty much like the CO₂ Ice on Mars. Those things are far away still, so I can live with the fake.