The UK Met Office improves its forecasts and reduces flight delays

This upgrade will refine cloud and fog predictions and enable earlier warnings to be issued, particularly for air travel

The UK Met Office has announced a major upgrade to its forecasting system, powered by its supercomputer. This upgrade will refine cloud and fog predictions and enable earlier warnings to be issued, particularly for air travel.

This is the most significant evolution of the Met Office's forecasting models in over three years. The upgrade aims to provide clearer and more precise bulletins, particularly regarding challenging weather phenomena such as low clouds, mist and fog, which often result in capacity restrictions at airports. Winter temperature forecasts are also more accurate, providing valuable information for managing the electricity grid, road salting, and de-icing. Most importantly, thanks to the extension of the overall forecast horizon from seven to ten days, warnings of hazardous weather can now be issued earlier.

The upgrade enables the public agency to enhance cloud representation in its models by refining layer heights and improving the detection of mist and fog. Simulated rainfall intensities are also more realistic, which is a crucial factor for anticipating operational conditions. These advances should facilitate the planning of rotations, adjustments to low-visibility slots, and de-icing operations. This is the first major upgrade since the decision was made in May last year to adopt this Microsoft-supplied supercomputer.

“The Met Office’s new supercomputer has allowed more accurate forecasting, particularly for cloud and fog, two difficult areas for forecasting”, summarises Minister of State for Science, Research and Innovation, Patrick Vallance. “Improvements in weather science benefit us all, from more flights running on time, to roads being gritted when they need to be, to enabling earlier preparations for storms that risk lives and damage to homes and businesses.”

Rain: the Achilles' heel of British aviation

The aim is to reduce the uncertainty caused by the weather, which leads to delays cascading through the system. In congested hubs like Heathrow, flying just a few dozen metres above the cloud base can result in stricter minimums being imposed and punctuality being disrupted. By issuing earlier alerts, airport operators and air traffic control have more advance notice to organise resources on the tarmac, in the control room and on the ground."

“We made a range of improvements, first and very topical at the moment is the UK’s rainfall, so the quality of our rainfall forecasts has improved very markedly, says The Met Office’s director of science, Simon Vosper. “We’re getting much more realistic rainfall intensities from the modelling system.”

British airports are particularly susceptible to weather-related delays. In a 2024 report by Eurocontrol, Heathrow and Gatwick, alongside Porto Airport, were among the top three airports experiencing severe weather-related disruptions. Skyrefund, a company specialising in passenger compensation procedures, also ranked the UK as one of the “worst destinations” in terms of delays and cancellations during the summer of 2025.