In South Africa, efforts to introduce summer ("daylight saving") time (DST) has and will always by stymied by the considerable east-west extent of the country. During the summer, we have the same time as Namibia - which is then on "daylight saving" time - and there is no reason for the time in Cape Town, on the same latitude as Namibia, to be different. Should the western part of the country then switch to the time zone of Namibia (UTC+1 with DST), the eastern part would surely stay on the present (UTC+2) time zone, perhaps introducing DST and perhaps not. The confusion generated by such a move would be considerable. The blog Freakonomics has furthermore just revealed the environmental effect of DST to be not negligible but actually negative. A study,
Does Daylight Saving Time Save Energy? Evidence From a Natural Experiment in Indiana by Matthew J. Kotchen and Laura E. Grant
has just revealed that DST increases the residential demand for electricity in the US state of Indiana - probably due to increase demand for heating and cooling. Ouch!