Weather

In the British Isles

The word weather describes the state of

the air at a particular place and time,

whether it is warm or cold, wet or dry,

and how cloudy or windy it is.

How the Sun makes our weather

The heat from the Sun warms up the layer

of air that covers our Earth. The cycle of

day and night warming and cooling moves

the air and means it can hold more or less

water droplets. This makes the wind...

Wind

The big layer of air around the Earth

is called the atmosphere. The air in

this layer moves from place to place

when it warms up or cools down. This

moving air is known as wind. Winds

move moisture and heat around the

world and also produce much of our

weather.

Ways we use the wind’s power

Damage caused by strong winds.Trees blown down in a storm.

Rain, thunder and lightning

It rains when warm moist air cools and

condensation occurs. Warm air can hold

more water than cool air, and when the

warmer air is cooled the moisture

condenses to liquid - and it rains.

Lightning is a bright flash of electricity produced by a thunderstorm. In a

thundercloud many small bits of ice (frozen raindrops) bump into each other as they move around in the air and they create an electrical charge. When a lightning bolt travels from the cloud to the ground it actually opens up a little

space in the air. Afterwards the air rushes back in and creates a sound wave that we

hear as thunder.

Storm clouds

Lightning

©Axel Rouvin

Rain falling from storm clouds

Fog and Mist

Mist and fog look like smoke,

but they are actually tiny drops of water floating in the air. They

are like clouds that have formed at ground level.

Fog

Mist

Snow and IceSnow forms when water vapour in the atmosphere freezes into ice crystals. These are six-pointed crystals that fall in clumps and sometimes you might see them on your clothes if you are out when it’s snowing.

When water gets very cold it freezes into ice. It swells up and takes up more space when it freezes so sometimes pipes burst. Birds and animals can often walk on the ice on lakes and ponds, but usually the layer of ice is too thin for us to walk on.

A snowy day in the park

Fun in the snow

Icicles on trees

Clouds and what they mean

There are a range of different types of clouds, the main three types are stratus, cumulus and cirrus.Stratus clouds are flat and unremarkable, appearing like layered sheets.Cumulus clouds are puffy, like cotton wool floating in the sky.Cirrus clouds are thin and wispy, appearing high in the sky.

A cloud is a large group of tiny water droplets that we can see in the air.

Small fluffy cumulus clouds – fine weather.

“Mare’s tails” – can mean worse weather on its way.

“Mackerel sky” – storms on the way.

Not clouds at all...

but vapour trails from airplane engines

Sunshine, SunsetsSunlight is composed of a spectrum of colours that ranges from violet and blue at one end to orange and red on the other. At sunrise or sunset, when the sun is lower in the sky, the light takes a much longer path through the atmosphere than during the middle part of the day. More violet and blue light is scattered out of the beam along the way, and so the light which reaches our eyes early or late in the day is red.

Clouds in the evening

Rainbows and Sun Dogs

Red

Orange

Yellow

Green

Blue

Indigo

Violet

These colours are always in a rainbow, Light from the sun divides up into these colours through a prism made by water droplets in clouds.

Sometimes the rainbow seems to come down to earth

A double rainbow

The colours of the top rainbow are

reversed.

Parhelia or Sundogs

Sundogs may appear as a rainbow

coloured patch of light either side of the

sun.

A very old story says that the sun was really a

God called Helios, who drove his chariot

pulled by great horses across the sky from

morning until night, and the hunting dogs that

ran alongside him made the lights we now call

Sun Dogs.

“Sun dogs”

Sometimes it’s only possible to see one of these, the other will be on the opposite side of the sun.