What is Weather & Climate

What is Weather?

Weather is how the atmosphere is behaving on a day to day basis, including temperature, rain and wind. These can change hour by hour, day by day. The weather affects everyday life. Each day it can affect choices we make about whether to walk or take the car, what clothes we wear and whether outdoor events and pursuits are likely to get glorious sunshine or be rained off. The weather we experience differs around the world. Even across Britain we experience a wide range of different weather types. So, while the weather brings different temperatures all over the world every day, over a year we'd expect the global climate to bring an average temperature of between 14 and 15 °C.

How does the Met Office (UK) make a weather forecast?

First, they have to collect observations To make a forecast, they have to understand what the weather is doing now. To do this, we receive millions of observations covering the entire planet. Observations of the weather are made 24 hours a day, all over the world. As well as taking measurements over land with lots of different types of equipment, they collect information from the ocean’s surface using ships and buoys, from high in the atmosphere thanks to satellites and weather balloons, and from deep in the oceans using a network of special instruments called Argo floats.

They then use computer models to produce a weather forecast. All this observational information is beamed back to the Met Office headquarters and fed into their supercomputer. This high performance machine, capable of doing more than a 125 trillion calculations a second, takes this information as a starting point to run complex equations built on the fundamental laws of physics.

With more than a million lines of code, the equations form a mathematical model designed to mirror the dynamics of the atmosphere and oceans. By putting current weather observations into the model, the computer generates simulations of what might happen next.

Finally, they use their expertise. Output from the supercomputer is then studied by experienced forecasters who look at a range of information to determine the accuracy of the simulations. Forecasters use their knowledge to compare the predictions of the models against actual observations. If necessary they can amend and add finer points to the forecasts before they are broadcast on television, radio and the internet, and delivered to a broad range of customers.

What is Climate?

The word ‘climate’ is derived from the Ancient Greek ‘klima’, meaning ‘zone’ or ‘region’. Today, many people from the UK travel south to the Mediterranean for their summer holidays as it’s more likely to be hot and sunny there. Variations in weather mean that holidaymakers could still experience damp days but on average, the weather is likely to be better in the Mediterranean during the summer because it’s in a different climate zone.

There are different climate zones because the Sun heats the tropics much more strongly than thepoles. This sets up large-scale wind patterns in the atmosphere and ocean currents which try to reduce the imbalance by moving heat (the energy cycle) and water (the water cycle) around the Earth.

What is the difference between weather and climate?

Weather is how the atmosphere is behaving on a day to day basis including temperature, rain and wind. These can change hour by hour, day by day. Climate on the other hand looks at how the weather changes over a long period of time, typically over 30 years but sometimes over hundreds of thousands of years.

Climate is what you expect, weather is what you get