Prosper in a dynamic world
Search

Wet season arriving in WA this week

Rain and thunderstorms will replace extreme heat over large areas of WA this week, with some places in the state’s north likely to see enough rain to officially mark the start of the wet season.

In Australia, the northern wet season is defined as the date after September 1 when at least 50 mm of rain has accumulated. This amount of rain is generally enough to stimulate plant growth after the dry season in northern Australia.

The map below shows that the 2023-24 northern rainfall onset occurred between September and December for large areas of Qld, the NT and the Kimberley in WA. However, as of late February, the wet season was yet to begin over parts of northwestern Australia.

Image: Northern rainfall onset date observations for the 2023-24 wet season, as of February 27, 2024. Source: Bureau of Meteorology

While the 2023-24 wet season arrived early for some areas further east, many northern and interior areas of WA have been locked in a pattern of unusually dry and extremely hot weather since the start of this year.

At the end of February, Port Hedland had only received 25 mm of rain since the start of September, which is half of what it needs to kick off the wet season. In an average wet season, Port Hedland usually reaches 50 mm of accumulated rainfall by late-January.

Image: Port Hedland’s wet season rainfall to date, compared to its long-term wet season average.

WA just registered its hottest summer on record, with a mean temperature that was 1.90C above the 1961-1990 average. More locally, Carnarvon’s 49.9ºC towards the end of the season was the 2nd highest temperature ever recorded in Australia during February. This came as Perth registered seven days over 40ºC during February, the city’s most 40ºC days on record in a single calendar month.

This run of intense heat is finally coming to an end, with cloud starting to build over WA as tropical moisture feeds into a series of low pressure troughs.

Importantly, these rain-bearing troughs are expected to linger over the north and interior of WA for most at least a week thanks to blocking high pressure systems near southeastern Australia. This should help kick off the wet season in some areas of northern Australia.

Image: Forecast accumulated rain this week, according to the ECMWF-HRES model.

This week’s rain and storms will erode the hot air mass that has plagued WA for the last few months.

The maps below show the daily maximum temperature forecasts from mid-February and on Thursday this week, highlighting the contrast in maximum temperatures.

Images: Maximum temperature forecasts for February 18 (top) and March 7 (bottom), according to the ECMWF-HRES model.

While the cooler temperatures and wet weather are likely to be welcomed with open arms by many across WA this week, the rain will be heavy enough to cause flooding in some areas.

A flood watch has been issued for the state’s Salt Lake District and Nullarbor District Rivers and Sandy Desert, warning that significant river, creek, and stream rises are likely with heavy rainfall, with flooding and overland inundation possible.

Be sure to check the latest flood watches and warnings across WA over the next few weeks.

To find out more about our Mining Services and lightning alerting please email us at apac.sales@dtn.com.

Latest news

Satisfy your weather obsession with these news headlines from around the nation, and the world.

Fiji surf pro finals day forecast and how DTN APAC supports live events

The final event of the 2025 surfing world tour will be run on a single day at Cloudbreak, in Fiji, in the coming two weeks, what waves will be on offer? After a year of great waves across the surfing world tour, only 10 competitors remain. On the women’s side, the final five ranking goes […]

Typhoon Kajiki to bring flooding and destructive winds to Southeast Asia

Typhoon Kajiki is starting to bring flooding rainfall, destructive winds and large waves to parts of Southeast Asia. Kajiki is the 23rd tropical depression in the Pacific region in 2025, and the 14th to develop into at least a tropical storm this season. As of 10am local time on Sunday, August 24, 2025, Kajiki was […]

Relentless NSW rain brings flooding, disruptions and Sydney’s wettest August day in nearly two decades

Relentless rainfall has soaked already sodden areas of eastern NSW this week, leading to flooding, road and rail disruptions, and Sydney’s wettest August day in nearly two decades. A deep stream of moist easterly winds has cause rain to soak parts of NSW and southeast Queensland every day between Monday and Friday this week. Most […]

Negative Indian Ocean Dipole gaining strength ahead of wet spring for many Australian businesses

One of Australia’s key climate drivers is gaining strength over the Indian Ocean, firming up the odds of a wet spring for large parts of the country. The Indian Ocean Dipole (IOD) refers to an index that measures the difference in sea surface temperature anomalies across the tropical Indian Ocean. It’s an index watched closely […]