An outbreak of thunderstorms has caused prolific lightning across Western Australia during the last few days, with more than 1.3 million lightning pulses detected over the state within 48 hours.

A slow-moving low pressure trough being fed with tropical moisture caused thunderstorms over WA on the weekend. While storms are not uncommon in WA at this time of year, this system has caused an unusually large amount of lightning over the same area for a prolonged period.

Thunderstorms affected a huge area of WA over the weekend, stretching from the south coast up to the Kimberley and from the Interior to the west coast.

The DTN Total Lightning Network registered 1,383,798 lightning pulses within 800 km of Leonora during the 48 hours ending at 8am AWST on Monday, September 28, 2026. The bulk of this lightning – roughly 900,000 pulses – occurred during the 24 hours ending at 8am on Monday.

The weather station at Kalgoorlie–Boulder Airport received 66 mm of rain between last Friday morning and this Monday morning. This three-day total is about five times their September monthly average.

September has been an active month for thunderstorm activity in WA thanks to frequent low pressure troughs sitting over the state and regular injections of tropical moisture from the Indian Ocean.

This pattern of recurring storms is associated with El Niño and a developing positive Indian Ocean Dipole (IOD), which are known to make high pressure systems more common to the south of Australia, which helps trap storm-producing troughs of low pressure over WA.

Image: Individual Lightning Strikes, available with a Pro subscription on the Weatherzone app.

Rain and thunderstorms will continue to affect a broad area of WA this week between Monday and at least Friday. This will likely include at least another 1,000,000 lightning strikes over the state and another 30–60 mm of rain in some areas.