How to get data data from site periodically and automated?

Problem: I need to take a ferryboat every weekday to get to my job, so I check the ferryboat's website to check the estimated delay time or if the line is too big.

The website only shows the current estimated time and refreshes it every 15 min I guess. So there is a number like: Delay = 20 min.

What I want to do: I want to get that number from the page (at every 1 hour) and save it automatically into a database somewhere so I can generate a chart, showing the patterns of the delay, and so on.

I have an intermediate javascript level. Thanks.