A night of relentless rainfall has left parts of Townsville underwater, with 24-hour rainfall totals which were the highest in 27 years.

In the 24 hours to 9am Wednesday (AEST):

• Townsville received a total of 301.4mm, the city’s heaviest day of rain in any month in 27 years.
• The 24-hour rainfall was more than one-and-a-half times the March monthly average of 188.9mm.
• The heaviest rain occurred between 1am and 9am, with a remarkable 241.4mm in eight hours.
• Other nearby weather stations exceeded 300mm, including a station at Horseshoe Bay on Magnetic Island, just off Townsville, which recorded 351mm.

What caused such an intense overnight deluge?

The eight-hour period of intensely heavy rainfall was caused by a moisture-laden onshore flow combined with a coastal trough, with the effect compounded by the southern inflow into the developing monsoon trough.

Image: Eight-hour radar loop centred on Townsville, Qld, between 1am and 9am AEST on Wednesday, March 19, 2025.

It also appears likely that a mesoscale low (a small-scale, short-lived low pressure area often associated with locally severe weather) formed over the ranges southeast of Townsville. This created an area of intense convection which was virtually stationary overnight, dragging in rain from the northwest and the east.

This is not the first deluge of this magnitude in Townsville this year.

In early February, Townsville received 284mm of rain in 24 hours, 545mm in 48 hours, and a whopping 710mm in 72 hours, in what was rarer than a one-in-2000-year event.

The good news is that the 48-hour and 72-hour totals from that event are unlikely to be matched in the current drenching. While heavy rain is possible at times today and into Thursday, the huge band of rain which inundated Townsville and nearby areas overnight had started to move southeast of the city by 10am local time.

However, the situation on the ground in Townsville remains extremely serious, with numerous road and school closures.

Please check the Weatherzone warnings page and the Queensland Government Disaster Management website for the latest flood information.