G5 iMac Fan Speeds/Temps?

I have a 20" Rev A G5 iMac. I wouldn't say it's overly noisy (I know there were some rogue ones) but I'm a little surprised how much the fans seem to have ramped up with the recent spate of warm weather.

Right now I'm seeing the following number using X Resource Graph:

CPU T-Diode 56.5 degrees C
Hard Drive 53 degrees C
CPU fan 2221 rpm
Hard Drive 3421 rpm
System Fan 2536 rpm

I'm assuming X Resource Graph is detecting the right sensors and reporting correctly etc. but does this look about right?

I know there's a lot of variables but the Mac isn't doing much right now and obviously there's no central heating on so it's just sat in a "normal" room with the windows open - no load as such.

cheers,
Paul