Get the max value per date based in serial

I have 3 fields Serial, Date and Temp.  The date field is actually a date time field I converted to just a date.  I am trying to get the max Temp per date for each serial number.  

In the past I have done this to get the max date of each serial and filter on only the columns with 1.

Max Date = IF('Export'[datetime]=CALCULATE(MAX('Export'[datetime]),ALLEXCEPT('Export','Export'[serialnumber])),1,0)

The complexity here is adding the Temp.  I need to flag each row somehow that this is the max temp for that serial on that day.

Here is a sample of what I am trying to do.  I dont necessarly need a max temp column with 1,0 but that how I was able to do it before.