Metering Shortcuts: "blue northern sky on a clear day"

[Philflash]

This is my first read of "Exposure" 2nd edition. Jeff suggests that as a metering shortcut we can meter "the blue northern sky on a clear day" to get an 18 percent/medium gray readout. Does the southern hemisphere get a different readout? I'm planning to visit New Zealand next year. What about it?

[PWS-Staff]

I might suggest going to you local camera store and purchasing an 18% grey card. Make a few comparisons against it under different conditions and make note of them. The palm of your hand, by the way, makes a good 18% "grey card."

[Tina]

OMG the palm of your hand really? Wow that's good to know! It's like always...you know....with you!