There is no such direct answer for the query, because earth,sun and all stars are in this sky only. So we can not say any distance between these two. What ever we are seeing above the ground is sky, it around the earth because earth in the sky. But most of the people intension about sky is cloud, so we can say the approximate distance between earth and cloud is around 2 Km to 18KM based on the place and climate. High clouds form at altitudes of 3,000 to 7,600 m in the polar regions, 5,000 to 12,200 m in the temperate regions and 6,100 to 18,300 m in the tropics. Mid level clouds can form as low as 2,000 m above surface at any latitude, but may be based as high as 4,000 m near the poles, 7,000 m at mid latitudes, and 7,600 m (25,000 ft) in the tropics. Low clouds are found from near surface up to 2,000 m.Earth's atmosphere can be divided into five main layers.
The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about 12 km, although this altitude actually varies from about 9 km (30,000 ft) at the poles to 17 km (56,000 ft) at the equator, with some variation due to weather. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i.e. a layer of relatively warm air above a colder one), and in others by a zone which is isothermal with height.
Although variations do occur, the temperature usually declines with increasing altitude in the troposphere because the troposphere is mostly heated through energy transfer from the surface. Thus, the lowest part of the troposphere (i.e. Earth's surface) is typically the warmest section of the troposphere. This promotes vertical mixing. The troposphere contains roughly 80% of the mass of Earth's atmosphere. The troposphere is denser than all its overlying atmospheric layers because a larger atmospheric weight sits on top of the troposphere and causes it to be most severely compressed. Fifty percent of the total mass of the atmosphere is located in the lower 5.6 km (18,000 ft) of the troposphere.
Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place. It has basically all the weather-associated cloud genus types generated by active wind circulation, although very tall cumulonimbus thunder clouds can penetrate the tropopause from below and rise into the lower part of the stratosphere. Most conventional aviation activity takes place in the troposphere, and it is the only layer that can be accessed by propeller-driven aircraft.