The mercury is set to soar by the end of this week and is predicted to break December records from more than 65 years ago.
On December 21, 1953, the Wagga mercury hit 43.2 degrees and could be broken this week.
According to the Bureau of Meteorology, the forecast is expected to reach a maximum of 44 degrees on December 19 and the 21st.
The highest minimum temperature ever recorded for December in Wagga was 29.8 degrees in 1994.
However, it is expected overnight temperatures this week will provide some relief with temperatures dropping down to 15 degrees.
Monday is expected to reach a top of 34 degrees, sunny, Tuesday reaching 37 degrees, Wednesday 40 degrees, Thursday up to 44 degrees, Friday 43 and then Saturday climbing to 44 degrees.
The highest temperature ever recorded in Wagga was 45.2 degrees in mid-January 2019 and 10 years ago in February.
A BOM duty forecaster said it's not just Wagga that has the potential to break records, with a proportion of Australia's mercury set to climb.
The NSW Rural Fire Service has issued a total fire ban for the Riverina, with a 'very high' fire danger rating.
"With winds forecast to be 35-55 kilometres per hour,the temperature 33 [degrees] and the relative humidity 13 per cent; should a fire occur and establish a foothold, it could potentially spread at a rate in excess of 10 km/h," said a Facebook post.