Wet Water evaporates into the air from oceans, rivers and lakes all the time. Some of this moisture stays in the air as invisible water vapour, giving air its humidity. Some water vapour, though, is carried high up by rising air currents. Here it is so cold that the vapour condenses into clouds of water droplets. When the droplets become too big to be borne up by the air, they fall as rain.
Air rising sharply creates tall clouds, such as thunderclouds, which give brief, heavy showers.
Air rising gently, as at a warm front, gives longer, steadier rain. Warmth Depends largely on the amount of sunshine and the cloud cover. Clear, anticyclonic weather gives the hottest days and the coldest nights because there are no clouds to keep the Sun's rays out or hold in any warmth at night. Why the sky is blue Every colour in the sky comes from the Sun. Sunlight is white, which means it is a mixture of all the colours in the rainbow.