Home
Weather London
WeatherRadar
RainfallRadar
TemperatureRadar
WindRadar
LightningRadar
Weather News
Editor's Pick
Discover the app
Weather widget
Contact us
Apps
Career
    Home / Editor's Pick /

    How are weather forecasts created?

07:00
15 March 2022

British Science Week
How are weather forecasts created?

There is no better time to look deeper into meteorology than on British Science Week. Starting with the world of forecasts.

Meteorologists use some of the world’s most powerful super-computers to produce our weather forecasts.

These incorporate a vast amount of data and perform trillions of calculations per second to give us an idea of how the weather will change in the coming days.

Due to the complexity of the atmosphere however, even these weather forecasts tend to only be reliable for up to five days or so.

If the weather conditions are particularly complex, there can still be a degree of error even within the five-day period.

Any forecast that offers an outlook greater than ten days’ time is not considered a forecast but a trend.

To produce these forecasts, meteorologists usually run their forecast models a number of times and group the forecasts into what are known as clusters.

This gives probabilities of what may happen in the future, rather than one single solution.

Short-term forecasts cover a period of 24 hours up to three days. We see these on the TV every day. They are generated using synoptic meteorology – current atmospheric observations – and numerical models.

Medium-range forecasts cover between three and 10 days with long-term forecasts covering periods over 10 days away. Both are generated by using weather ensemble models to create a weather trend.

For both ranges, conditions tend to be described as wetter or drier, warmer or cooler with no specific information.

Ryan Hathaway
More on the topic
Heavier rainfall over the week for some. Ireland & Scotland. . . Tuesday, 28 July 2026
Split image showing a Europe rainfall accumulation forecast map on the left with the highest totals across the UK, Ireland, and Scandinavia, and a satellite weather map on the right with a broad band of rain stretching across Ireland, Scotland, and northern Britain, highlighted by a rain cloud icon.
Tuesday, 28 July 2026

Ireland & Scotland

Heavier rainfall over the week for some
Catastrophic forest fires in Europe. Thousands evacuated. . . Monday, 27 July 2026
A composite image showing a temperature map of south-western Europe and a drone shot of a forest fire near Cap Ferret. A warning symbol featuring a flame indicates the increased risk of forest fires.
Monday, 27 July 2026

Thousands evacuated

Catastrophic forest fires in Europe
Icy spells in the Southern Hemisphere. Snow in the Andes. . . Tuesday, 28 July 2026
A composite image showing a temperature radar map of South America and a snow-covered town in Chile. The winter cold is bringing heavy snowfall to the Andes and, in some areas, snow down to lower altitudes.
Tuesday, 28 July 2026

Snow in the Andes

Icy spells in the Southern Hemisphere
All weather news
This might also interest you
A frozen start to the weekend. Icy conditions. . . Friday, 13 February 2026
UK temperature map dated 14.02 showing widespread subzero values in blue shading, with readings such as −4 in Glasgow, −3 in Dublin, and −2 in London, alongside a blue thermometer icon.
Friday, 13 February 2026

Icy conditions

A frozen start to the weekend
New records for England and Wales. Broken again tomorrow?. . . Thursday, 25 June 2026
Temperature map of southwest Britain on 25.06 showing extreme heat across southern Wales and southwest England, with Bute Park in Cardiff highlighted at 34.2°C and Yeovilton at 36.4°C amid widespread deep red heat zones.
Thursday, 25 June 2026

Broken again tomorrow?

New records for England and Wales
Turbulent weather in the Canary Islands. Storm and rain. . . Friday, 12 December 2025
Weather graphic showing rain and wind fields over the Canary Islands and a central warning symbol.
Friday, 12 December 2025

Storm and rain

Turbulent weather in the Canary Islands
All articles
Weather & Radar

Weather & Radar is also available on

Google Play StoreApp Store

Company

Contact us Privacy Policy Legal info Accessibility statement

Services

Uploader

Socials

facebooktwittertikToklinkList