Any wares to calculate the world time for me?

[Zhengquan Zhang mailing list <zhang.zhengquan.mailinglist@gmail.com>]

I use kworldclock to see what the time now is at another place in the world.
But what should I use to see what time is at another place at a future time?

Thanks!

-- 
Zhengquan Zhang 
Department of Electronic Engineering
Tsinghua University
Beijing,P.R.China.