Heavy rain is drenching Western Australia's Pilbara district this week, with some areas receiving more than three times their entire monthly average in just two days.

The early-winter soaking is being caused by a slow-moving low pressure through passing over the Pilbara, which is being fed by copious amounts of moisture from the nearby Indian Ocean.

So, how unusual is it for the Pilbara to see this much rain at this time of year?

On average, Port Hedland usually receives 24mm of rain during June, while a typical February, which is the wettest month, would see 94mm. During the 24 hours to 9am on Thursday, Port Hedland received 52mm of rain, which is its wettest June day in five years.

Further inland, Wittenoom's 58mm during the 24 hours to 9am today was its heaviest daily total for June in 25 years. The site has now collected 95mm during the last two days, which is more than three times its June monthly average of 28mm.

This system will continue to cause further heavy rain in the east Pilbara on Thursday, with a severe weather warning and flood watch currently in place.

Looking ahead, rain will ease from Friday as the low pressure trough moves further east and starts to weaken.