Sydney is sweating through its hottest day in 12 months as power outages affected the city’s eastern suburbs on Thursday morning.

Ausgrid confirmed on Thursday morning that power was out to about 45,000 properties.

The energy provider said emergency crews were investigating outages in suburbs across the city’s east, including Randwick, Bondi Junction, Bondi, Kensington, Waverley, Double Bay and Woollahra.

The outage had affected the University of New South Wales, where the campus was in darkness on Thursday morning. The Waverley magistrates court was also been evacuated.

Power is out to about 45,000 customers in Sydney's eastern suburbs. Emergency crews are on the way to investigate and restore power. Impacted areas include Randwick, Bondi Junction, Bondi, Kensington, Waverley, Double Bay, Woollahra. For updates go to https://t.co/MxbaFPxBlK pic.twitter.com/bX77lbsOJK — Ausgrid (@Ausgrid) January 31, 2019

Ausgrid confirmed the outages had been addressed by early afternoon.

Sydney’s CBD and harbourside suburbs are expected to hit 40C today, before a cool change arrives in the evening.

Rebecca Farr, a forecaster at the Bureau of Meteorology, said the last time Sydney’s Observatory Hill recorded 40C was January 7, 2018, when the mercury hit 43.4C.

“In general it’s relatively rare for Observatory Hill to reach 40 because normally the sea breeze will moderate those temperatures,” she said.

“It’s in those rare situations where the sea breeze doesn’t come in that we see temperatures that are more like something we’d see in the western suburbs.”

⚠️We've issued a #SevereWeatherWarning for Damaging Winds with a gusty southerly change expected for the #Illawarra, #Sydney and Central Coast late this afternoon and during the evening.

Latest warnings: https://t.co/QdHH05QCos pic.twitter.com/QM3fG0LD9M — Bureau of Meteorology, New South Wales (@BOM_NSW) January 30, 2019

nightmare outside the magistrates court as all of the courtrooms evacuated because of power failure — Brigid Delaney (@BrigidWD) January 31, 2019

Relief is on the way though. Farr said a southerly wind coming up the coast of NSW was expected to hit Sydney by the early evening.

“At this stage it looks like Sydney will see a fairly reasonable temperature drop,” she said.

“Basically we’re forecasting 40 today, and overnight the city will see temperatures of about 19 out west and 21 for the city.

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.

“Tomorrow there will be a top of 25 for the city and 26 for western suburbs.”

The bureau has issued a severe weather warning for damaging winds for the Illawarra, Sydney and central coast late this afternoon and during the evening.

The cool change won’t last long though, with the bureau predicting highs of 29 in the city on Sunday and 30 in the western suburbs.