Sydney was pelted with hailstones as a severe thunderstorm swept over the city on Wednesday night, before blowing out minutes later.

Heavy rain, thunder and hail hit the city just after 8.30pm, ending an otherwise dry day with a high temperature of 32 degrees.

The inflated Santas aboard the South Steyne before they were torn from their lashings in the storm.

Sydneysiders were also treated to a spectacular light show as lightning bolts lit up the skyline.

The storm came shortly after the Bureau of Meteorology issued an updated severe thunderstorm warning at 8.21pm for the metropolitan area, as well the northern rivers, parts of the mid north coast, Hunter, Illawarra, Central Tablelands, Central West Slopes and Plains and Northern Tablelands Forecast Districts.