data=numpy.loadtxt("file.txt")
hour=data[:,3]
day=data[:,4]
temp=data[:,5]
load=data[:,6]
a=multipolyfit.multipolyfit(numpy.vstack((hour,day,temp)).T, load, 2)
print a

[ 27011.    771.   5462.   -394.    -29.    -83.     10.   -804.      9.      1]