9.7ºC

The thermal's temperature at the surface is 25ºC.

The thermal's temperature would drop at the DALR
for the first kilometer (-9.8ºC)...

The thermal's temperature would drop at the SALR
for the second kilometer (-5.5ºC)...

25ºC - 9.8ºC - 5.5ºC = 9.7ºC