[citation][nom]decepticon[/nom]This probably would not work well in very hot climates as the temp difference between the ground and your feet wouldn't be that much.[/citation]
Why would you wear Wellies in hot countries? Wellies are to keep your feed dry, implying a wet environmonet.
As long as there is a temperature difference, be it positive (ie hotter insode the boot than outside) or negative (cooler in the boot than outside)the boots would generate electricity.