Clouds

Cumulus

Mostly fair weather clouds, well delimited in the sky; these are the clouds that children draw, and that philosophers use as examples when discussing the phenomenon of vagueness ;-)

Altocumulus

A cloud that wanders around 3000m, it can have a very wide variety of forms (saying this about any cloud is probably not very informative, now I think about it ;-). If there is a thick layer of altocumulus there will very likely be some rain in the next couple of hours. If they stand alone however, they announce a fine weather.

Lenticular Altocumulus

Situated between 2'000m and 4'000m, they usually are a sign of a strong wind.

Cumulonimbus

A very big (several kilometers across) storm-announcing cloud. It can be as wide as 20km. The one below is very small, it's something between a cumulus and a cumulonimbus; I still have to take a better photo here :-)

Cirrus

Thin clouds high in the sky. They usually never cover the whole sky, and they are situated between 5'000m and 10'000m. Often, they announce a forthcoming change in the weather in the next days : rain.

Cirrostratus

A thin cloud very high in the sky, it is often like a thin veil, and you can see the sun through it. If it covers the whole of the sky, it announced rain in the next hours.

Stratus

A low-situated cloud, between 0m and 500m. When it is really low, it is a fog. It's probably not a surprise that the next two photos were taken in ... Ireland ;-)

Stratocumulus

A more-or-less thick layer of cumulus, usually a couple of hundered meters thick, situated between 1'000m and 2'000m. Usually, they end up transformed into cumulus, but sometimes they can stick around for quite a long time.

Altostratus

A uniform layer of clouds, at about 3'000m; if it thickens it announces rain.

Nimbostratus

A bad weather cloud located between 1'500m and 5'000m, often accompanied by rain - if it is cold enough, the rain becomes snow.

An ocean of clouds

A layer of stratus or stratocumulus seen from above.

Rays of light

Usually, this can be seen when the sun shines through holes in thick clouds, so it means that rain is in the neighbourhood.

Blue sky

The sky is more or less blue depending on humidity and pollution of the air. Well, in my case it also depends on the filter I use ;-)

The red sun

When the sun is very low in the sky, the rays have to cover a longer distance in the atmosphere, which plays a role of a filter that stops first the blue part of the spectrum, then the green one, and then the yellow. In the end, only the red part remains.