Met Office scientists apply aviation technology to complete Santa’s Christmas Eve deliveries when his reindeer are stuck by seasonal sniffles.
It’s the late hours of Christmas Eve, and Santa faces an unprecedented challenge: most of his reindeer have come down with the seasonal sniffles. With just one determined reindeer flying, Santa’s usual lightning speed is reduced to the speed of a typical airplane - and he still has three crucial stops to make: Lapland to reload, then on to London and finally New York.
How will he manage? And will he be on time?
This is where Met Office science steps in. Our advanced trajectory prediction technology – the same system that calculates cost-efficient routes through complex weather systems for aviation industry partners – is being put to a unique festive use. Using the same scientific principles that guide thousands of journeys daily, we’re helping Santa plan the most efficient path through international airspace.
The science behind Santa's new route
The challenge: Airlines prefer flight routes that are safe and efficient, but current systems don't fully account for weather uncertainty. While weather centres have introduced new forecasting techniques to account for uncertainty, such as ensembles, it could be tricky to implement and convey the benefits in existing commercial flight planning systems.
The solution: Met Office scientists have developed a new route-planning system that uses a variant of Dijkstra's algorithm (a mathematical way of finding optimal paths) to calculate the most efficient flight paths. The system processes real-time weather conditions, including wind patterns and potential hazards like turbulence. It can calculate multiple route options based on different priorities - whether that's minimising flight time, maximising fuel efficiency, or avoiding weather hazards - and has been designed to integrate smoothly with existing commercial flight planning systems.
Real-world application: When tested on a London Heathrow to Los Angeles flight route, where turbulence had been reported over Greenland, the system proved its worth. It not only identified the fastest possible route but also calculated safer alternatives at the cost of increased fuel to avoid turbulent areas. The analysis showed precise trade-offs helping airlines make informed decisions before take-off rather than requiring last-minute changes.
Santa's one reindeer-sleigh-challenge
How can this system help Santa with his new route? For Santa's reduced-speed journey, our system can calculate the optimal path between Lapland, London and New York based on the weather conditions across different time zones and conditions on Christmas Eve. By mapping areas of turbulence and identifying opportunities to utilise tailwinds while avoiding headwinds, we can help Santa's remaining reindeer conserve energy while maintaining critical delivery schedules.
Historical data
Using historical data, we've analysed Santa's journey times over the past decade (2013-2023) over the Christmas period. Our trajectory prediction algorithm, assuming a departure from Lapland at 12:00 UTC and from London at 15:00 UTC, shows fascinating variations in optimal flight paths. When Santa's reindeer flies at a fixed airspeed, the most time-efficient routes vary significantly based on weather conditions. Our analysis reveals different patterns of flight paths across the years, with some routes taking more northerly tracks while others drift further south, all depending on the positioning of weather systems and jet streams.
Figure 1: Probability distribution function showing how long Santa's Lapland-London-New York journey typically takes around Christmas, based on data from the past decade. The green line shows the overall range of journey times in 2013-2023, while the red line is our prediction for Christmas Eve 2024.
Figure 2: Our 'spaghetti plot' shows the variety of routes Santa could take. Each green line represents the optimal path for different Christmases, demonstrating how weather patterns influence the best route choice. The red line shows the optimal path for Christmas Eve 2024. The Great Circles (the shortest route between airports) are marked in black as reference.
Santa’s journey in 2024
For Christmas Eve 2024, our latest calculations show that Santa's Lapland-London-New York journey will take approximately 9 hours 38 minutes, which is about the average Christmas Eve journey over the past decade. We expect the Lapland-London leg to follow a route towards the southeast, and the London to New York leg to take a slightly northerly route from the great circle. Note that there are still five nights’ sleep until Christmas and this year’s prediction was made using weather forecast at longer lead times. As a result, the uncertainty of Santa's journey times this year is naturally higher as reflected by the width of the bell curve.
The bigger picture
This festive application demonstrates how our system helps reduce environmental impact through intelligent routing while maximising natural weather advantages. The technology delivers multiple advantages: more predictable flight times and fuel consumption, reduced risk of weather-related disruption, and enhanced pre-flight decision-making capabilities. As it integrates with existing systems, it supports the aviation industry's wider move towards better understanding of weather uncertainties and decision making with their trajectory-based operations.
And while we can't guarantee Santa will make all his deliveries on time this Christmas, we can ensure his remaining reindeer gets the safest and most efficient route possible through our skies. 🎄