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I would use =countif(b2:b100,">0) to determine number of data points

(I will assume your data starts in row 2)

then

=offset(c1,countif(b2:b100,">0"),0) will be the last calculated number in column C

if you need, you could put in error protection for any case where no value in column B is >0

=if(max(b2:b100=0,0,offset(d1,countif(b2:b100,">0"),0))

I do assume there will be no hourly rate<0

another approach would be to use

=rounddown((now()-today()),0)*24-1 to determine how many hours
of data for today you will have, and then match this number in column a
to find your data point.