Time synch

I know that the time synchs as the box boots up but this relys on an internet connection being available at boot time. Unfortunately, my internet connection takes ages to establish and the box is up before the connection exists. I'd like to put a command in the cron file to do a time synch at 00:10 on 1st January so that the box can get a time update if there has been a power cut.

Can anyone point me in the direction of how to do this? ntpdate doesn't seem to be installed.