The wind, flowing over the whole planet

What you are looking at

Each streak is a particle dropped into the wind ten metres above the ground and carried along by it. Together they draw what no weather icon can: the steady trade winds either side of the equator, the great westerly storms circling Antarctica, the spiral of every cyclone, the calm in the middle of a high. The colour is the speed — faint for a breeze, cyan for a fresh wind, yellow for a gale, magenta for a storm. On an equal-area map a storm takes up exactly as much room as it really covers.

How to read it

• Faster, brighter streaks mean stronger wind: magenta is storm force, above about 60 km/h.
• A spiral is a low — a storm or a cyclone — turning anticlockwise north of the equator and clockwise south of it.
• Switch on Storms & hazards with it to see each cyclone's name and forecast track inside its spiral.

Questions

Where is it windiest right now?

The figure at the top of this page names the place with the strongest wind on the model's grid at this hour. Most days it is somewhere in the Southern Ocean, in the belt of westerlies sailors call the Roaring Forties — unless a tropical cyclone is out-blowing it.

Why do storms spin in different directions?

Because the Earth turns. Air moving towards a low is deflected to the right in the northern hemisphere and to the left in the southern — the Coriolis effect — so lows turn anticlockwise in the north and clockwise in the south. On the equator itself there is no deflection, which is why cyclones never form there.

Is this the real wind or a forecast?

It is the weather model's best estimate for this hour: observations from stations, ships, aircraft and satellites are fed into the model every six hours, and the field shown is the step nearest to now. Over open ocean it is usually within a few km/h of what a ship would measure; in mountains and cities the real wind varies far more than a one-degree grid can show.