This is the definition of a heatwave from the Bureau of Meteorology in Australia:
http://www.bom.gov.au/metadata/catalogue/19115/ANZCW0503900601#:~:text=Abstract,climate and the recent past.
The Bureau of Meteorology defines a heatwave as three or more days in a row when both daytime and night-time temperatures are unusually high in relation to the local long-term climate and the recent past.
This falls within all definitions of a heatwave I have seen. I say again temperatures are within April maximums and thus not unusual. The unusual thing is it's everyday.