Severe thunderstorms rumbled across the Sydney basin on Christmas Eve, delivering heavy rainfall leading to significant disruption at Sydney Airport during the busiest time of the year. 

Image: Sydney Airport time series showing the heavy and rapid rainfall falling on Christmas Eve. 

A slow-moving severe thunderstorm developed over the Sydney basin yesterday, causing heavy rainfall, with 37mm being recorded in the 20-minute period to 5:10pm AEDT at the airport, with a greater total of 73mm falling in the hour to 5:30pm AEDT overall. This heavy rainfall caused localised flooding on the tarmac, leading to flight delays, diversions and cancellations, severely disrupting holiday flights. 

In the 24-hour period to 9am on Christmas day, the Airport recorded a grand total of 91.2mm, making it the wettest December day in 53 years. For what it’s worth, this was also the wettest Christmas Day on record for the station (rainfall being recorded in the 24 hours to 9am each day, with records going as far back as 1939 for Sydney Airport). 

Further intense thunderstorm activity will affect broad parts of eastern Australia on Christmas Day and Boxing Day as a broad low-pressure trough slowly tracks eastwards, possibly causing further disruptions over this holiday period.