I am all for watering after the sun goes down when the weather is dry. However, this business of water drops burning leaves is a myth.
For one thing, water drops conduct heat well enough for the drop to be fairly uniform in temperature.
A cite confirming the myth status:
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That cite also says some bad things about evening watering, which I think mostly don't apply in dry areas or during dry weather. The one that I think does apply is if plants are obviously badly in need of water and their condition could deteriorate if you wait until evening - but then again, they should have been watered early that morning or the evening before.
- Don Klipstein ( snipped-for-privacy@misty.com)