Extreme temperatures are persisting – and even peaking – in Victoria and New South Wales on the fifth day of Australia’s extraordinary, record-breaking heatwave with Noona in western NSW recording a minimum temperature of 35.9C, a new Australian heat record.

On Friday, parts of NSW and the ACT were again forecast to soar above 40C – for the fifth day in a row.

Nine records were broken in NSW on Wednesday, and more are forecast to fall on Friday.

In Penrith in Sydney’s west, temperatures will hit 45C, up from 42C on Thursday. In Menindee – the site of mass fish kills in the Murray river – another 45C day is on the cards. It reached 47C on Wednesday and Thursday, and the maximum temperature hasn’t been below 45C since Monday.

Australia has a new heat record! Overnight, #Noona in the #NSW west recorded a 35.9C MINIMUM temperature. It's the latest in a series of broken records in this #heatwave

Heatwaves are dangerous - stay hydrated & look out for others! #beattheheat

Forecast: https://t.co/nTTbM3WZEP — Bureau of Meteorology, New South Wales (@BOM_NSW) January 18, 2019

Rebecca Farr, a forecaster for the Bureau of Meteorology, said Canberra would break the record for the longest stretch of over-40C days since records began in 1939.

“For Canberra, today we are forecasting 40C and, if we reach that, it will the the first time on record that we will have four consecutive days of 40C or more,” she said.

“Broken Hill is forecast to hit four consecutive days of 45C, and that also hasn’t happened before. Records there started in 1957.”

The northern regions of Victoria, including Mildura, Shepparton and the border towns of Albury-Wodonga, will also stay above 40C.

Quick Guide Heatwaves and climate change in Australia Show According to the Bureau of Meteorology and the CSIRO, Australia has warmed by 1C since 1910, and temperatures will increase in the future. So how will climate change affect future heatwaves in Australia? The CSIRO and BoM have compiled different models for predicting the outcome of climate change in Australia to produce a guide to how different regions will likely be affected. They found that every part of Australia will continue to experience increases in average temperature, and will have a higher frequency of hot days.

The duration of hot spells will increase in every region. In many areas in the northern half of Australia, the average number of days above 35C could increase by two to three times.

Late in the century, towns such as Darwin, Alice Springs and Broome may experience days with temperatures above 35C for about a third of the year. These higher temperatures will also result in higher evaporation, which will continue to make drought conditions worse.

But southern and coastal regions will experience the welcome relief of sub-30 temperatures and even rain. Melbourne is set for a maximum of 28C, Geelong 26C and Warrnambool 21C.

It will also cool in South Australia, at least compared with the record-breaking 48.9C recorded in Port Augusta on Tuesday.

Temperatures will still hover in the 30s but the stretch of nearly-50C temperatures looks to be over.

Port Augusta is set for 32C (down from 48.9C), Tarcoola 31C (down from 48.7C), Coober Pedy 38C (down from 47.8C) and Woomera 37C (down from 47.6C).

But central Australia will remain scorching. Oodnadatta – one of the hottest 15 places in the Earth this week – will still sit at 46C.

In NSW, the towns of Ivanhoe, Bourke and Wilcannia are all facing 46C. Gundagai will swelter through 44C, which is only slightly down on the 45C experienced on Wednesday.

Farr said the summer had smashed records across the state.

“Yesterday we saw some January records broken,” Farr said. “Cobar (47.2C), Parkes (44.5C), Wagga (45.2C) and Tuggeranong (40.8C) all had their hottest January day since records began.

“On Wednesday, we even saw some annual records broken. It was the hottest day since records began at Broken Hill airport (46.3C), Whitecliff (48.2C), Wilcannia (47.9C) and Albury (45.6C).”

Temperatures in NSW are expected to drop over the weekend. Menindee is set for 36C with some cloud cover and Penrith 32C. Wilcannia and Ivanhoe will drop to 40C, but Bourke is set to stay hot at 45C on Saturday, and hold at over 40C through all of next week.