grub2: different default OS at different time?

[Marosi Csaba]

Hi,
my problem is the following: I have a *remote machine* with Linux and
Windows. I want to use it through SSH or RDP respectively, but when I
restart it, the default OS is linux, so it boots linux and I can't use
the local keyboard to change. If I change the default OS, then I could
not start linux because from windows I don't know how to change back
the grub's default OS.

Anyway, my solution for this would be that I tell grub2, when there is
odd hour, boot windows, when even, boot linux. This would be a perfect
solution for me, because I only need to reboot in the right time. I am
quite sure that it is possible, but I could not google how to do it.

Can you tell me how to do this, or give an other workaround to this problem.
Thank you!
Regards,
Csaba Marosi